DE9402729U1 - Shrink core for concrete pipes - Google Patents

Description

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H. NIEMEYER SÖHNE GMBH & CO. KG 21 February 1994

PO Box 11 65 Big./Av

48466 Hörstel-Riesenbeck

Shrink core for concrete pipes

The invention relates to a shrink core for producing pipes made of concrete or the like in a design according to the preamble of claim 1.

In a known shrink core of this type, the shrink core casing1 that forms the inner contour of the concrete pipe consists essentially of a core casing that is one piece around the circumference and has a locking wedge that is hydraulically drawn into the shrink core when it is activated and at the same time causes the core casing to contract by means of a rod. This measure allows the core to be easily removed from the concrete pipe after it has been removed from the mold.

Larger concrete pipes of this type are easier to access on the inside, so that the hydraulic adjustment elements of the shrink core for adjusting the locking wedge can be anchored to the bottom of the core, for example. The adjustment mechanism of the shrink core takes up a relatively large amount of space and is difficult to install due to the length of the core.

DE 30 49 492 C2 discloses a locking wedge for a shrink core which is designed in such a way that it can be extended against stops by the hydraulic adjustment elements of the shrink core. This works well, but is complex to manufacture.

The object of the invention is to create a shrink core of the type mentioned in the preamble of claim 1, the adjustment elements of which can be attached in a space-saving manner and are easy to assemble while being structurally very simple.

The invention solves this problem with the characterizing features of claim 1. With regard to further essential embodiments, reference is made to claims 2 to 7.

The shrink core according to the invention essentially consists of three parts in the area of the core shell, which form the effective shape. A lower part, which preferably also forms the lower part of the concrete pipe, a side part on each side and a locking wedge, which, like the other parts of the core shell, extends over the entire length of the concrete pipe to be formed.

Before the parts are joined together during the manufacture of the core shell, the upper part of the core shell, consisting of the two side parts and the adjusting wedge, can be pre-assembled with the preferably hydraulic adjusting elements according to the invention. This makes the adjusting elements easily accessible. The double-acting hydraulic cylinders used, for example, are connected to the side parts of the core shell in an articulated manner by means of straps. The adjusting wedge is infinitely adjustable in length to the outer contour of the core shell, so that the adjusting wedge advantageously does not require any stops and can only be adjusted by a single

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Adjustment in the area of the lifting cylinder after the piston has been extended into its final position. The infinitely variable adjustment option of all hydraulic cylinders for adjusting the adjustment wedge ensures easy adjustment and uniform end position of the adjustment wedge over its entire length. Seals are provided in the area of the flanks of the adjustment wedge, which protect the interior of the shrink core when the adjustment wedge is closed.
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According to the invention, the lower part and the side parts of the core jacket are detachably connected to one another, preferably by a screw connection.

According to the invention, it is further provided that each hydraulic cylinder of the adjustment elements is connected in an articulated manner to the side parts of the core casing via tabs. If the rod side of the hydraulic cylinder is pressurized with oil, the locking wedge is first drawn in and at the same time the shrink core casing is pulled together in the area of the opening of the locking wedge so that it can be released from the concrete and easily removed. For this purpose, all hydraulic cylinders are preferably connected in parallel so that they can be operated simultaneously.

A significant advantage of a shrink core according to the invention is that, thanks to the advantageous design, shrink cores can be used for concrete pipes of smaller dimensions and/or, for example, for egg-shaped pipes with smaller dimensions while maintaining the same pipe length. Another advantage is the simple initial assembly. The detachable connection of the core shell parts means that the adjustment elements remain easily accessible for maintenance work.

An embodiment of the invention is shown in the following drawings.

It shows:

Fig. 1 - The front view of a shrink core after

Invention.
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Fig. 2 - The side view of the shrink core according to Fig. 1,

Drawn rotated 90°.

Fig. 3 - Section A-B according to Fig. 2, drawn rotated by 90°.

Fig. 4 - Detail X according to Fig. 3, in enlarged scale.

Fig. 5 - The shrink core according to section AB Fig. 3, but
shown in a shrunken state.

Fig. 1 shows the front side of an egg-shaped shrink core (1) for producing pipes made of concrete or the like. It essentially consists of the smooth core casing (2), which is mainly made up of a lower part (3), a right side part (4), a left side part (5) and a locking wedge (6) on the circumference. The shrink core (1) is shown in the position in which the concrete pipe is in use. In the area of the two ends of the pipe, the lower part (3), the right side part (4) and the left side part (5) are each reinforced by a rib (7,8,9).

Furthermore, Fig. 1 shows the locking wedge (6) in the closed position, as the shrink core assumes when forming the concrete pipe. In this position, the double-acting hydraulic cylinder (10) is pressurized by oil on the piston side, so that the piston rod (11) is extended to the piston stop. In this position, the locking wedge (6) reaches its end position and the core casing (2) is closed.

The hydraulic connecting parts have been omitted from all figures. The same applies to the external formwork required for the manufacture of the concrete pipe and the pipe itself.
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The hydraulic cylinder (10) is connected to the side parts (4,5) on both sides around the articulation points (12,13,14) by means of double brackets (15,16). Connecting brackets (18,19) take over the lateral guidance of the hydraulic cylinder (10).

Depending on the length of the concrete pipe to be formed, several hydraulic adjustment elements (17) are arranged in the shrink core (1). They are hydraulically connected in parallel so that they react simultaneously when pressurized oil is applied.

In Fig. 2, the shrink core (1) is shown in a shortened side view. In this case, three adjustment elements (17) are evenly distributed over the length of the shrink core (I).

Fig. 3 shows the shrink core (1) in a view of section A-B from Fig. 2 rotated by 90°. The sectional view of the hydraulic cylinder (10) has been omitted.

As in Fig. 1, the piston rod (11) of the hydraulic cylinder (10) is extended so that the locking wedge (6) is closed. The locking wedge (6) with the webs (21) is connected at the articulation point (36) by a joint piece (20) to the piston rod (11) of the hydraulic cylinder (10) by means of an adjusting thread (22). At the end of the piston rod (11) there is preferably an external thread which is screwed into the internal thread of the joint piece (20). Two symmetrically arranged guide surfaces (24) on the piston rod (11) serve as a base for an open-end wrench.

When adjusting the locking wedge (6) in the pre-assembled

Condition of the adjustment elements (17), the side parts (4,5) and the locking wedge (6), with the piston of the hydraulic cylinder (10) extended, the adjustment threads (22) are adjusted so that the outer contour of the adjustment wedge (6) is flush with the core casing (2). The adjustment is then secured in each case by a lock nut (23). In this closed position, the adjustment wedge (6) rests against the wedge-shaped guide surfaces (38,39).

Longitudinal grooves (25) are provided in the locking wedge (6), in each of which a seal (26), for example a round cord ring, is inserted in order to protect the interior of the shrink core (1) from contamination when the locking wedge (6) is closed.

Connecting tabs (18,19) at the hinge point (27) are articulated on the hinge piece (20). The connecting tabs (18,19) are also articulated to the hinge points (13,14), which in turn are movably arranged in the reinforcing ribs (28,29). The reinforcing ribs (28,29) are attached in the area of the adjustment elements (17) and are firmly connected to the side parts (4,5). They also represent the connection to the longitudinal reinforcements (30,31), which on the other hand form the seam to the detachable lower part (3).

Reinforcements (32,33) are provided at the upper ends of the lower part (3) over the entire length of the shrink core (I). Their inner side rests on the outer side of the longitudinal reinforcements (30,31) and is guided there. The connection between the longitudinal reinforcements (30,31) and the reinforcements (32,33) is formed by screws (34) that are evenly distributed along the length of the shrink core (1). These are preferably countersunk screws with hexagon sockets in order to obtain a smooth surface in the area of the core shell (2) on the one hand and to ensure that the screws

to be able to tighten the screws correctly using the hexagon socket. In order to only have to operate the screws (34) from the outside, an internal thread (37) is provided in the screw area of the longitudinal reinforcements (30, 31), as shown enlarged in detail X in Fig. 4.

The shrink position of the shrink core (I) is shown in Fig. 5. The rod side of the hydraulic cylinder (10) is pressurized with oil so that the piston rod (11) retracts as far as the piston stops. The hydraulic cylinder (10) is supported around the hinge point (12) via the tabs (15,16) in the hinge points (13,14). The piston rod (11) moves the locking wedge (6) into the interior of the shrink core (1) and at the same time the connecting tabs (18,19) pivot around the hinge points (13,14,27) so that the side parts (4,5) are pivoted inwards around the lower part (3) in a spring-loaded manner, whereby the outer circumference of the shrink core (1) is reduced and thus detaches itself from the interior of the concrete pipe. After this process, the shrink core (1) can be removed axially from the finished concrete pipe.

Claims (7)

H. NIEMEYER SÖHNE GMBH & CO. KG 21 February 1994 PO Box 11 65 Big./Av 48466 Hörstel-Riesenbeck CLAIMS 1. Shrink core for concrete pipes, consisting of a one-piece core casing and an actuating device for the shrink core by means of a hydraulic adjusting element which moves a locking wedge with a stop and is supported on the opposite base inside the shrink core, characterized in that the shrink core casing (2) consists of at least three detachably connected parts (3,4,5) and a locking wedge (6) which is adjustable by means of at least one hydraulic adjusting element (17). 2. Shrink core according to claim 1, characterized in that the articulation points (13, 14) of the hydraulic adjustment element (17) for adjusting the closure wedge (6) are arranged in the region of the gap (35) to be closed by the closure wedge (6) in the interior of the shrink core casing (2). 3. Shrink core according to one of claims 1 or 2, characterized in that the end position of the closure wedge (6) relative to the outer diameter of the shrink core casing (2) is continuously adjustable. · 2· · 4. Shrink core according to one of claims 1 to 3, characterized in that the hydraulic adjusting element (17) is formed by a double-acting hydraulic cylinder (10), a joint piece (20) and tabs (15, 16, 18, 19). 5. Shrink core according to one of claims 1 to 4, characterized in that the hydraulic cylinder (10) can be supported on the shrink core casing (2) by at least two articulated tabs (15, 16) and is guided by at least two connecting tabs (18, 19). 6. Shrink core according to one of claims 1 to 5, characterized in that the shrink core casing (2) and the locking wedge (6) can be actuated in a lifting movement of the hydraulic cylinder (10). 7. Shrink core according to one of claims 1 to 6, characterized in that when several hydraulic adjustment elements (17) are arranged per shrink core (1), these are hydraulically connected in parallel.