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Patent Searching and Data


Title:
FORMWORK APPARATUS
Document Type and Number:
WIPO Patent Application WO/2021/190747
Kind Code:
A1
Abstract:
A formwork apparatus (1, 101) comprising: a first portion (2) which is fixable on a formwork base (8); and a second portion (3) for defining an outer dimension of a concrete element (4), which is movable between a work position, at which the concrete element (4) can be fabricated, and a retracted position, at which the finished concrete element (4) is allowed to be removed. In order to fabricate concrete elements (4) with reduced effort, the formwork apparatus is configured such that the second portion (3) can be held at the work position at least partially via the first portion (2) when the first portion (2) is fixed on the formwork base (8), and the second portion (3) is movable between the work position and the retracted position relative to the first portion (2) at least when the first portion (2) is fixed on the formwork base (8) and the second portion (3) is not held at the work position.

Application Number:
PCT/EP2020/058400
Publication Date:
September 30, 2021
Filing Date:
March 25, 2020
Export Citation:
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Assignee:
BT INNOVATION GMBH (DE)
International Classes:
B28B7/00
Attorney, Agent or Firm:
KOCH, Jens (DE)
Download PDF:
Claims:
Claims:

1. Formwork apparatus (1 , 101) for fabricating concrete elements (4), the formwork apparatus (1) comprising: a first portion (2) which is fixable on a formwork base (8); and a second portion (3) for defining an outer dimension of the concrete element (4), which is movable between a work position, at which the concrete element (4) can be fabricated, and a retracted position, at which the finished concrete element (4) is allowed to be removed, wherein the formwork apparatus (1) is configured such that the second portion (3) can be held at the work position at least partially via the first portion (2) when the first portion (2) is fixed on the formwork base (8), and wherein the second portion (3) is movable between the work position and the retracted position relative to the first portion (2) at least when the first portion (2) is fixed on the formwork base (8) and the second portion (3) is not held at the work position.

2. The formwork apparatus (1, 101) according to claim 1, wherein the formwork apparatus (1) is configured such that the second portion (3) is held at the work position completely via the first portion (2).

3. The formwork apparatus (1, 101) according to claim 1 or 2, wherein the formwork apparatus (1) comprises a holding unit (6, 106) comprising at least one transferable member (61, 1061) which is transferable between a holding state and a non-holding state, wherein at the holding state, the transferable member (61, 1061) is coupled to the first portion (2) such that the second portion (3) is held at the work position at least partially via the transferable member (61, 1061), wherein the holding unit (6) preferably comprises at Seas! one self-locking chock (61) contactable with the second portion (63) and coupleable to the first portion (2) in the holding state, as the transferable member and/or the holding unit (106) comprises at least one transferable member (1061) provided at the second portion (3) and one receiving member (1062) provided at the first portion (2) and engageable with the transferable member (1061).

4. The formwork apparatus (1, 101) according to any of the preceding claims, wherein the second portion (3) is biased in at least a direction towards the concrete element (4) to be fabricated or a direction towards the formwork base (8) at the work position.

5. The formwork apparatus (1, 101) according to any of the preceding claims, wherein the first portion (2) defines the work position of the second portion (3),

6. The formwork apparatus (1, 101) according to claim 5, wherein the first portion (2) comprises a stop part {21), wherein the second portion (3) abuts against the stop part (21) at the work position, preferably the stop part (21) is a chamfer strip to be in contact with the concrete element (4) to be fabricated.

7. The formwork apparatus (1, 101) according to any of the preceding claims, wherein the formwork apparatus (1) is configured such that the second portion (3) moves at least with a direction component facing away from the formwork base (8) between the work position and the retracted position, preferably, rotates with respect to the first portion (2).

8. The formwork apparatus (1, 101) according to any of the preceding claims, wherein the second portion (3) comprises a support part (32) and a concrete forming part (31) for direct contact with the concrete element (4) to be fabricated which is detachably attached to the support part (32).

9. The formwork apparatus (1, 101) according to any of the preceding claims, wherein the first portion (2) is fixed to the formwork base (8) via a magnetic force.

10. The formwork apparatus (1 , 101) according to claim 9, wherein the formwork apparatus (1) further comprises a magnetic unit (5) which is transferable between a lowered position, in which the first portion (2) is fixed to the formwork base (8) by magnetic interaction between the magnetic unit (5) and the formwork base (8), and a raised position, in which the first portion (2) is movable relative to the formwork base (8) due to reduced, preferably, cancelled magnetic interaction between the magnetic unit (5) and the formwork base (8), and is coupled to the first portion (2) at least in the lowered position.

11. The formwork apparatus (1, 101) according to claim 10, wherein the first portion (2) comprises an accommodation space (23) in which the magnetic unit (5) is accommodated, and the magnetic unit (5) is coupled to the first portion (2) within said accommodation space (23).

12. The formwork apparatus (1, 101) according to claim 10 or 11, wherein the second portion (3) covers at least the magnetic unit (5) and, preferably, the accommodation space (23), at least at the work position.

13. The formwork apparatus (1 , 101) according to any one of claims 10 to 12, wherein the formwork apparatus (1) further comprises an activation unit (11), which can be coupled to the magnetic unit (5) for transferring the magnetic unit (5) between the towered and the raised position.

14. The formwork apparatus (1, 101) according to claim 13, wherein the activation unit {11) can be coupled to the magnetic unit (5) only at the work position of the second portion (3).

15. The formwork apparatus (1, 101) according to claim 13 or 14, wherein the formwork apparatus (1) is configured such that the activation unit (11) is moved linearly to transfer the magnetic unit between the lowered and raised position, preferably along a direction perpendicular to the formwork base (8).

Description:
Formwork Apparatus

The present disclosure relates to a formwork apparatus for fabricating concrete elements.

For the fabrication of concrete finished elements formwork so used. It is state of the art to fix formworks to a formwork base. The fixed formwork constitutes the negative of the concrete element to be fabricated together with the formwork base.

In particular, formworks with a U-shaped profile are fixed to the formwork base by a magnetic force. Therefore, a magnetic unit is arranged inside of the U-shaped profile and is transferable between a lowered and a raised position. In the lowered position, the magnetic unit is in a strong magnetic interaction with the ferromagnetic formwork base and is coupled to the formwork such that it presses the formwork against the formwork base as disclosed in DE 10 2018 212 422. For the transfer between the lowered position and the raised position, an activation unit is provided which exerts a force onto the magnetic unit to raise or sink the magnetic unit In DE 102018212422, the activation unit is detachable from the magnetic unit when the magnetic unit presses the formwork to the formwork base (work position of the formwork). Thereby, the upper surface of the formwork can be made smooth. This ensures that the upper surface of the concrete element can be easily worked, as working machines can easily pass over the formwork.

However, after fabrication of the concrete element, it might be necessary to remove the formwork from the work position in order to remove the concrete element For example, in case of intersections preventing the concrete element from being removed, the entire formwork has to be detached from the formwork base and is displaced relative to the formwork base in order to remove the fabricated concrete element However, the steps of positioning, fixing, detaching are cumbersome, even more if several concrete elements with the same outer dimension need to be fabricated.

It is therefore an object of the present disclosure to provide a formwork apparatus with which concrete elements with similar outer dimensions can be fabricated with reduced effort.

The above object is achieved by a formwork apparatus according to claim 1.

According to a first aspect a formwork apparatus for fabricating concrete elements is provided, comprising: a first portion which is fixable on a formwork base; and a second portion for defining an outer dimension of the concrete element, which is movable between a work position, at which the concrete element can be fabricated, and a retracted position, at which the finished concrete element is allowed to be removed. The formwork apparatus is configured such that the second portion can be held at the work position at least partially via the first portion when the first portion is fixed on the formwork base. The second portion is movable between the work position and the retracted position relative to the first portion at least when the first portion is fixed on the formwork base and the second portion is not held at the work position.

The second portion can be moved between the work position and the retracted position with the first portion fixed to the formwork base. Thereby, the concrete element can be taken out easily. At the work position, the fixed first portion at least partially contributes to holding the second portion at the work position. Hence, the effort for re-establishing the work position can be reduced in comparison to the case where the entire formwork apparatus needs to be fixed again to the formwork base.

Preferably, the formwork apparatus is configured such that the second portion is held at the work position completely via the first portion. Thereby, the effort is even more reduced and no additional elements need to be provided to hold the second portion at the work position with respect to the formwork base.

Preferably, the formwork apparatus comprises a holding unit comprising at least one transferable member which is transferable between a holding state and a non-holding state, wherein, at the holding state, the transferable member is coupled to the first portion such that the second portion is held at the work position at least partially via the transferable member.

Thereby, the second portion can be reliably held at the work position via the first portion, In addition, the holding state might be easily cancelled in order to allow movement of the second portion to the retracted position via the transferable member. ore preferably, the transferable member is detachably fixable to the first portion.

The holding unit preferably comprises at least one self-locking chock contactable with the second portion and coupleable to the first portion in the holding state, as the transferable member.

Holding at the work position can be further facilitated by such a self-locking chock as the number of elements can be reduced.

Preferably, the holding unit comprises at least one transferable member provided at the second portion and one receiving member provided at the first portion and engageable with the transferable member.

Such holding unit has the advantage of easy operation. In addition, attrition of the formwork apparatus is reduced.

Preferably, the second portion is biased in at least a direction towards the concrete element to be fabricated or a direction towards the formwork base at the work position.

This ensures that the second portion is more reliably held at the work position. Preferably, the first portion defines the work position of the second portion.

Hence, the number of components can be further reduced. No additional elements are needed to ensure the correct position of the second portion at the work position.

Preferably, the first portion comprises a stop part, wherein the second portion abuts against the stop part at the work position, preferably the stop part is a chamfer strip fo be in contact with the concrete element to be fabricated.

This is an easy way to ensure that the second portion is positioned correctly at the work position.

Preferably, the formwork apparatus is configured such that the second portion moves at least with a direction component facing away from the formwork base between the work position and the retracted position, preferably, rotates with respect to the first portion. More preferably, the second portion rotates around an axis parallel to an outer surface of the concrete element.

Hence, concrete or dirt accumulated at the formwork base and the first portion can be easily avoided. Furthermore, operability of the formwork apparatus is enhanced.

Preferably, the second portion comprises a support part and a concrete forming part for direct contact with the concrete element to be fabricated which is detachably attached to the support part.

Thereby, concrete elements with greater flexibility in the outer shape can be fabricated as the concrete forming part can be easily replaced.

Preferably, the first portion is fixed to the formwork base via a magnetic force.

Hence, the first portion can be reliably fixed to formwork base. With the invention, the times when the magnetic force needs to be cancelled to repeatedly fabricate concrete elements can be massively reduced.

Preferably, the formwork apparatus further comprises a magnetic unit which is transferable between a lowered position, in which the first portion is fixed to the formwork base by magnetic interaction between the magnetic unit and the formwork base, and a raised position, in which the first portion is movable relative to the formwork base due to reduced, preferably, cancelled magnetic interaction between the magnetic unit and the formwork base, and is coupled to the first portion at least in the lowered position.

Thereby, the first portion can be reliably pressed against the formwork base and transferred to the raised position for detaching the first portion from the formwork base. It is preferable, that the first portion comprises an accommodation space in which the magnetic unit is accommodated, and the magnetic unit is coupled to the first portion within said accommodation space.

Thereby, the magnetic unit is protected from environmental influences such as concrete and dirt. Additionally, the first portion can be made compact

More preferably, the second portion covers at least the magnetic unit and, preferably, the accommodation space, at least at the work position.

Thereby, the magnetic unit is protected from environmental influences such as concrete and dirt more reliably. Additionally, the formwork base can be made compact.

It is further preferred that the formwork apparatus further comprises an activation unit, which can be coupled to the magnetic unit for transferring the magnetic unit between the lowered and the raised position.

This enables an operator to easily transfer the magnetic unit between the lowered and the raised position.

Preferably, the activation unit can be coupled to the magnetic unit only at the work position of the second portion.

This provides a control that the second portion is actually at the work position. Furthermore, the activation unit may be used to maintain the work position.

Preferably, the formwork apparatus is configured such that the activation unit is moved linearly to transfer the magnetic unit between the lowered and raised position, preferably along a direction perpendicular to the formwork base.

Here, operation of the formwork apparatus is further improved. Additionally, fabrication of the formwork apparatus is facilitated as the access to the magnetic unit is facilitated. Also, the work range of an operator can be reduced.

For large heights of the concrete element, stronger magnets need to be provided as a larger fixation force is necessary to withstand the high pressures occurring during fabrication of concrete elements with large heights. However, using magnets providing larger forces impairs activation of the magnetic unit for transfer between the lowered and raised position. Hence, it is desired to provide a magnetic unit, which can be easily activated without causing damage to surrounding elements. In particular, this application also focuses on providing a magnetic unit with strong magnetic interaction, which can be easily transferred between a lowered and a raised position.

A further aspect of the application provides: A magnetic unit comprising: at least two magnetic packs which are a pack of magnetic and ferromagnetic elements and are pivotally supported at respective first support locations; an activation device for pivoting the magnetic packs between a lowered position in which the magnetic packs are in magnetic interaction with a ferromagnetic surface and a pivoted position in which the magnetic interaction is reduced in comparison to the lowered position, wherein the activation device is configured to at least temporarily jointly pivot the magnetic packs between the lowered position and the pivoted position.

According thereto, the magnetic unit has at least two magnetic packs, which ensure a sufficient magnetic interaction to reliably press an element towards the ferromagnetic surface. With the magnetic packs being pivotally supported, the magnetic interaction between the magnetic packs and the ferromagnetic surface can be continuously reduced by the pivoting movement, wherein the required activation force is significantly lower in comparison to a case where the magnetic packs are removed from the ferromagnetic surface in a mere translational manner. In addition, the activation can at least temporarily jointly pivot the magnetic packs between the lowered position and the pivoted position. This enables easy operability as an operator only needs to activate the activation device which then can pivot the plurality of magnetic packs together.

Preferably, at least some of the magnetic packs are pivotally supported at the same axis.

Thereby, the magnetic unit can be made compact and the number of parts can be reduced. This also enables a uniform load absorption at the axis.

Preferably, at least part of the activation device is configured to move translationally while pivoting the magnetic packs.

Thereby, an operator might move the activation device linearly while the magnetic packs pivot. This further enhances operability.

Preferably, the activation device is configured to at least temporarily jointly displace the magnetic packs translationally between the pivoted position and a raised position in which the magnetic interaction is further reduced in comparison to the pivoted position.

Once the magnetic interaction is reduced at the pivoted position, the magnetic interaction can be further reduced by removing the magnetic packs from the ferromagnetic surface in a translational manner. Thereby, the magnetic interaction can be massively reduced with a low activation force. Preferably, the activation device comprises a support unit at which at least some of the magnetic packs are pivotally supported at the respective first support locations.

According thereto, operability is further improved as the activation device has a common support unit.

Preferably, the activation device comprises a coupling unit at which the magnetic packs are jointly supported at respective second support locations for receiving a load causing the pivoting movement.

According thereto, it is possible to distribute an activation force (load) by one unit to the second support locations of the magnetic packs, which therefore are caused to pivot.

Preferably, the coupling unit comprises a central load introduction portion extending substantially centrally with respect to the coupling unit.

Thereby, the load can be easily introduced in a uniform manner, which facilitates operation. Additionally, the configuration can be made compact and easy.

Preferably, the magnetic packs are supported at the coupling unit such that they are allowed to move relative to the coupling unit along a direction crossing the relative displacement direction.

This ensures that the pivoting movement of the magnetic packs is not locked by the coupling unit.

Preferably, the coupling unit is linearly displaceable relative to the support unit along a relative displacement direction.

Thereby, pivoting movement is generated by a linear movement of the coupling unit, which can hence easily be activated. This further enhances operability.

Preferably, at least one of the coupling unit or the support unit comprises a central portion which is arranged between the magnetic packs and at which the magnetic packs are supported.

Thereby, the space between the magnetic packs is effectively used. In this way, the magnetic unit can be made compact

Preferably, a virtual connection between the respective first and second support locations is a lever direction, which crosses the relative displacement direction. It is more preferable that the lever direction and the relative displacement direction cross each other at a substantially right angle (70 s to 90°), more preferably at a right angle. Thereby, a momentum can be generated with respect to the first support location, which reliably pivots the magnetic packs. If the lever direction and the relative displacement direction cross each at a substantially right angle, a sufficient momentum can be effectively generated.

Preferably, the respective first and second support locations are located at opposite end sides of the magnetic packs along the lever direction, preferably with the center of gravity of the respective magnetic pack therebetween.

More preferably, the first or second support locations are located at a peripheral side with respect to the above mentioned central portion.

Thereby, an effective lever arm can be reliably provided. Hence, the necessary activation force to overcome the magnetic interaction can be reduced.

Preferably, the magnetic packs are arranged at equal intervals along a circumferential direction around a center between the magnetic packs.

Thereby, the magnetic packs can be arranged in a compact manner. Additionally, a uniform load distribution in the activation device is favoured.

More preferably, the magnetic unit is configured to be arranged symmetrically.

Thereby, the operability is further enhanced. In particular, the pivoting movement of the magnetic packs can occur at the same time and in a symmetric manner. Hence, the magnetic unit can be moved away from the formwork base along a predetermined trajectory.

It should be noted that the magnetic unit presented above is preferably used in a formwork apparatus according to the first aspect but may be used also in other formwork systems where magnetic interaction is required.

The aspects of the present disclosure will become more apparent by reading through the following detailed description in consideration of the accompanying drawings, which show:

Fig. 1A shows a side view of a formwork apparatus together with a concrete element with a second portion at the work position

Fig. 1 B shows a side view of the formwork apparatus of Fig, 1 A without the concrete element

Fig. 2 shows a side view of the formwork apparatus together with the concrete element with the second portion at the retracted position in which the concrete element can be taken out.

Fig. 3 shows a perspective view of the formwork apparatus from up and behind with a holding unit in a non-holding state

Fig. 4 shows an enlarged perspective view of the formwork apparatus with the holding unit in a holding state Fig. 5 shows a rearview of the formwork apparatus with a section through an accommodation space

Fig. 6 shows a side view of a modification of the formwork apparatus

Fig. 7 shows the formwork apparatus with another example of a holding unit in a non-holding state

Fig. 8 shows the formwork apparatus with the other example of the holding unit in a holding state

Fig. 9 shows a perspective view of a magnetic unit according to a further aspect in a lowered position

Fig, 10 shows a front view of the magnetic unit in the lowered position

Fig. 11 shows a front view of the magnetic unit in the pivoted position

Fig. 12 shows a front view of the magnetic unit in the raised position

In the following detailed description, spatial definitions such as front, back, upper, lower, and horizontal are not used in a restricting manner. These terms are merely used for explanatory reasons.

Figures 1A and 1B show a formwork apparatus 1 with a first portion 2 and a second portion 3 in a work position. As can be seen from Figures 1 A and 1 B, at the work position of the second portion 3 a concrete element 4 can be fabricated at a front side of the formwork apparatus 1. That is, at the work position a barrier for the not cured concrete is constituted by the formwork apparatus 1. The second portion 3 is provided with a concrete forming part 31, which comes in direct contact with the concrete to be cured. The concrete forming part 31 is the negative of the outer dimension of the fabricated concrete element 4. Thereby, the second portion 3 defines an outer dimension of the concrete element 4 via the concrete forming part 31.

It should be noted that in Figures 1A and 1B the outer dimension of the concrete element 4 is not only defined by the concrete forming part 31 of the second portion 3 but additionally by a first chamfer strip 21. First chamfer strip 21 is part of the first portion 2 and is integrally formed with a base part 20 extending substantially in a horizontal direction (front-rear direction) parallel to the framework base 8 in the side view of Figures 1A and 1B,

The concrete forming part 31 is provided with a second chamfer strip 311, at its upper side, which is a side distant from a framework base 8 in a direction perpendicular to the framework base 8 (vertical or up-down direction) in Figures 1A and 1B, which results in a chamfer of the fabricated concrete element 4. After fabrication of the concrete element 4, the chamfer strip 311 at the upper side impedes the removing operation of the concrete element 4 from the formwork apparatus 1. It is well known to accurately position and fix a formwork apparatus to a formwork base during fabrication of a concrete element in order to withstand the pressure occurring during the curing process. After fabrication of the concrete element, in case of intersections existing, for example, by the chamfer strip 311 , the entire formwork apparatus had to be detached from the formwork base and was displaced relative to the formwork base in order to remove the fabricated concrete element. However, the steps of positioning, fixing, detaching are cumbersome, even more if several concrete elements with the same outer dimension need to be fabricated.

The present disclosure is made in view of the foresaid and allows easy and repeated fabrication of concrete elements.

For this reason, the formwork apparatus 1 comprises the first portion 2 and the second portion 3 which is movable between the work position, as shown in Figures 1 A and 1 B, and a retracted position as shown in Figure 2, with respect to the first portion 2. The first portion 2 is fixable to the formwork base 8. The formwork apparatus 1 is configured such that the second portion 3 can be held at the work position at least partially via the first portion 2 when the first portion 3 is fixed on the formwork base 8. That is, when the first portion 2 is fixed to the formwork base 8, the first portion 2 is used to contribute to the holding of the second portion 3. Thereby, the second portion 3 can be held at the work position with reduced effort. It should be noted that the expression "held at the work position at least partially via the first portion’’ means that by at least part (components) of the forces acting on the second portion at the work position are transmitted to the first portion 3.

As the second portion 3 is held at the work position, relative movement of the entire formwork apparatus 1 with respect to the formwork base 8 is not possible. However, as the second portion 3 can be moved to a retracted position, it is still possible to take out the concrete element 4 after fabrication.

It is preferable, that the second portion 3 is coupled to the first portion 2 during the movement between the work position and the retracted position. As the second portion 3 is coupled to the first portion 2, the second portion 3 can reliably return to the work position from the retracted position. Hence, repeated fabrication of concrete elements with identical outer dimensions can be performed. It should be noted that it is preferable, as in the present case, that the second portion 3 is coupled to the first portion 2 such that it has one degree of freedom, more preferably, a rotation about an axis parallel to an extension direction (width direction) of the outer surface of the concrete element 4 to be defined by the concrete forming part 31. The first chamfer strip 21 has, as can be seen from Figures 1 and 2, a triangular cross-section. It has a first surface 21a which is in contact with the concrete element 4, thereby providing a chamfer at the lower edge of the concrete element 4, a second surface 21b, which rests on the formwork base 8 (together with rest parts provided to the base part 20 as can be seen in Figure 1A), and a third surface 21c, which stands up substantially vertically at a right angle to the lower second surface 21b. At the work position, the front side, which is a side at the concrete element 4, of the concrete forming part 31 abuts against the third surface 21c of the first chamfer strip 21. It should be noted that the third surface 21c is a back side of the first chamfer strip 21, which substantially faces away from the concrete element 4 along the horizontal direction parallel to the formwork base 8 (front-rear direction).

When the second portion 3 moves from the retracted position to the work position, the back side of the second chamfer strip 21 serves as a stop for the second portion 3, which ensures correct positioning of the second portion 3.

In the embodiment shown in Figures 1 and 2, the transfer between the work position and the retracted position is performed by a joint 7, which couples the second portion 3 and the first portion 2. The joint 7 of the present embodiment is preferably of a parallelogram-type. The joint 7 comprises two parallel horizontal flange elements 71 and 72 spaced apart from each other in the vertical direction, and two spaced apart parallel connecting elements 73 and 74 which connect the upper and lower flange elements 71 and 72 wherein at the respective upper and lower ends of each connecting element 73 and 74, bolts 75 pass through the connecting elements 73 and 74 and are supported by the flange elements 71 and 72.

As can be seen from Figures 1A, 1B, and 2, the concrete forming part 31 of the second portion 3 substantially stands up in the vertical direction which is a direction perpendicular to the formwork base 8 in the side view. A support part 32 extends substantially in a horizontal direction parallel to the framework base 8 in the side view, and integrally from an intermediate part of the concrete forming part 31. As can be seen from Figures 1 , 2, and 3, vertical portions 32b of the support part 32 at least sectionally bend downward along the vertical direction towards the framework base 8 at a rear side of the horizontal portion 32a of the support part 32.

As can be seen from Figure 3, the horizontal portion 32a of the support part 32 is fixed to the upper side, a side facing away from the formwork base 8, of the upper flange element 72 by screws. At some of the vertical portions 32b, a handle 9 is attached which can be operated by an operator of the formwork apparatus 1. The lower flange element 71 is fixed to the first portion 2. When movement of the second portion 3 with respect to the first portion 2 from the work position to the retracted position is to be performed, the operator simply pulls the handle 9. Thereby, a momentum acts on the parallelogram-type joint 7 which lets the second portion 3 (upper flange element 72) rotate (pivot) with respect to the first portion 2 (lower flange element 71). Due to the rotational movement, the second portion 3 does not only move horizontally, but also vertically. That is, the second portion 3 moves at least with a direction component facing away from the formwork base 8. The vertical movement allows easy retraction from the work position to the retracted position even if dirt has come between the first portion 2 and the second portion 3 during the fabrication process. The joint 7 from the parallelogram type has the advantage that the orientation of the second portion 3 does not change while being rotated. In particular, the second portion 3 passes a rotational trajectory from the work position to the retracted position but the orientation of the second portion 3 {horizontal portion 32a oriented horizontaily, vertical portion 32b oriented vertically, and concrete forming part 31 oriented substantially vertically in the side view) does not change. Thereby, other parts can be reliably covered as will be described later. In addition, such joint 7 allows the second portion 3 to retract directly, without interference with the concrete element 4, substantially along the horizontal direction (front-rear direction) in Figures 1A, 1B, and 2.

To withstand the pressure occurring during fabrication, the second portion 3 is required to be held at the work position. That is, a tight state between the back side 21c of the first chamfer strip 21 and the front side of the concrete forming part 31 of the second portion 3 is required to fabricate concrete element 4 accurately. Therefore, the second portion 3 needs to be held at the work position. In the present embodiment, as shown by Figures 1 to 4, holding units 6 are provided, which can hold the second portion 3 at the work position. In the present embodiment, the only degree of freedom of the second portion 3, which is not locked via the first portion 2 when the first portion 2 is fixed to the formwork base 8, is the pivoting movement around the joint axis. All other degrees of freedom are locked via the first portion 2. Hence, at the work position the second portion is held at least partially via the first portion 2.

It is preferable that the second portion 3 can be completely held at the work position via the first portion 2.

For this purpose, each holding unit 6 comprises a chock 61 as can be seen from, for example, Figure 3. The chocks 61 are provided at two sides along the extension direction (width direction) of the formwork apparatus 1, which is substantially the same as the extension direction of the outer surface of the concrete element 4. Only one chock 61 will be described in the following as the other one is provided symmetrically with respect to a retraction direction. The chock 61 is movable along a long slot 22 formed in the base part 20 of the first portion 2, as can be seen in Figures 3 and 4. Two screws 63 along the long slot 22 penetrate the long slot 22 and through holes of the chock 61 and are fastened by nuts 62 on the upper side of the chock 61. In Figure 3, the chock 61 is at a position which allows the second portion 3 to be moved relative to the first portion 2 from the work position to the retracted position and vice versa (non-holding state). When the second portion 3 is at the work position, the chocks 61 are moved to approach the second portion 3, in particular, the vertical portion 32b. Providing two chocks 61 at opposite sides along the extension direction (width direction) of the second portion 3 is preferable, as loads can be absorbed uniformly.

As the chock 61 has an inclined surface 61a with respect to the extension direction of the vertical portion 32, the inclined surface 61a makes contact with the vertical portion 32b even in case of manufacturing imprecisions. When contact between the chock 61 and the vertical portion 32b occurs, the chock 61 can be pressed further towards the vertical portion 32b. Thereby, a force towards the concrete element 4 acts on the second portion 3. In other words, the second portion 3 is biased in a direction towards the concrete element 4 and the back side of the first chamfer strip 21 , and hence, reliably abuts against the back side of the first chamfer strip 21. In that state, the nuts 62 are fastened, as shown in Figure 4 (holding state). Thereby, the chock as transferable member is fixed to the first portion 2.

Holding is performed, when a separating force, which tends to separate the second portion 3 from the first chamfer strip 21 , exceeding the biasing force acts on the second portion 3, as the chock 61 absorbs this excessive load and transmits it to the first portion 2, which is fixed to the formwork base 8. Preferably, the holding unit 6 provides a biasing force as in the present case.

For a compact and easy apparatus, it is preferable that the holding operation is completely performed by a flux of force between the second portion 3 and the first portion 2 as presented above. In other words, the second portion 3 is coupled to the first portion 2 at the work position such that all degrees of freedom are locked via the first portion 2.

Preferably, the inclined surface 61a of the chock 61 forms an acute angle with the extension direction of the vertical portion 32b, which is a direction substantially perpendicular to the retracting direction of the second portion 3. It should be noted that the retracting direction is determined by the direction of the tangent to the rotational trajectory of the second portion 3 at the fixing location of the second portion 3 to the joint 7 and is substantially parallel to the horizontal direction in Figures 1 and 2 which is a direction along which the second portion 3 separates in the fastest way. Thereby, a self-locking effect can be achieved, which prevents the second portion 3 from moving relative to the chock 61.

As it has been set forth above, for the second portion 3 being reliably held at the work position, it is necessary that the first portion 2 is fixed on the formwork base 8. The present disclosure is, in particular, advantageous in cases where the first portion 2 is fixed to the formwork base 8 via a magnetic force. That is, this fixation method provides stable fixation resisting high forces but is also cumbersome in detaching due to the high forces. Hence, it is beneficial if the first portion 2 can remain fixed for removing a concrete element.

In the embodiment, the first portion 2 is fixed to the formwork base 8 via a magnetic force, as it is disclosed, for example, in German patent application DE 10 2018 212422 whose content is incorporated herein by reference. For this purpose, the formwork apparatus 1 includes a magnetic unit 5. The formwork base 8 is further made of a ferromagnetic material such that magnetic interaction can occur between the magnetic unit 5 and the formwork base 8.

Reference is made to Figure 5. Therein, the magnetic unit 5 is shown in a lowered position. In the lowered position, the magnetic interaction with the formwork base 8 is high. In the lowered position, the magnetic unit 5 is coupled to the first portion 2 via bolts 10, which are attached to the first portion 2. The magnetic force is transmitted from the magnetic unit 5 to a head of the bolts 10, preferably with an elastic member interposed therebetween, and then to the first portion 2. By the magnetic force, the first portion 2 is pressed against the formwork base 8.

The magnetic unit 5, is transferable between the lowered position and a raised position. In the raised position, the magnetic interaction is massively reduced, preferably cancelled. Therefore, the first portion 2 can be displaced relative to the formwork base 8.

The transfer between the lowered position and the raised position is performed by an activation unit 11. The activation unit 11 is, for example, a screw, as shown in Figure 5 for the left and right magnetic units, and is threaded into a screw hole provided in the magnetic unit 5. For transfer between the lowered and raised position, the screw 11 is pulled upward or pushed downward, respectively.

The first portion 2 includes an accommodation space 23, in which the magnetic unit 5 is accommodated. The accommodation space 23 is surrounded by side walls 24a and 24b and upper wall 25 of the first portion 2. Side walls 24a and 24b substantially stand up vertically from the base part 20 and the upper wall connects them.

A through-hole 26 is formed in the upper wall 25, through which the screw 11 passes. Thereby, the screw 11 is only allowed to move along a direction perpendicular to the formwork base 8 in the present case.

The coupling of the magnetic unit 5 to the first portion 2 takes place within the accommodation space 23 by the bolts 10. Thereby, the formwork system 1 can be made compact, as no protruding elements exist. In addition, the magnetic unit 5 can be protected from dirt or liquid concrete by the surrounding walls. As can be seen from Figures 3 to 5, the screw does not only penetrate the upper wall 25 of the first portion 2 but also the horizontal portion 32a of the second portion 3. In particular, the horizontal portion 32a is provided with a through-hole 33 coaxial to the through-hole 26 in the upper wall 25. Thereby, the framework system can be easily manufactured as both through- holes can be manufactured together.

Through-hole 33 is further provided such that the activation unit 11 can be coupled to the magnetic unit 5 only at the work position. That is, the coaxial orientation between both through holes only exists at the work position of the second portion 3. This provides a control that the second portion 3 is actually at the work position. Furthermore, the movement between the work position and the retracted position of the second portion 3 is only possible with the activation unit 11 removed from the magnetic unit 5. This is preferable in comparison to a case where a long slot is provided instead of through-hole 33, as dust or concrete might enter the long slot, while the through-hole 33 can be covered by a plug. Hence, a smooth surface is provided.

With the configuration presented above, the same plug can be used for through-hole 33 and through-hole 26.

The second portion 3 covers the magnetic unit 5 as well as the accommodation space 23 from above that is from a side away from the formwork base 8 by the horizontal portion 32a. Additionally, it covers the magnetic unit 5 and the accommodation space 23 from the back by the vertical portion 32b. Furthermore, also the joint 7 is covered by the horizontal portion 32a

Therefore, dust and concrete can be reliably prevented from impairing function of the magnetic unit 5, the accommodation space 23, and the joint 7.

Modifications:

As presented above, the second portion 3 is provided with a concrete forming part 31 In the embodiment, the concrete forming part 31 was integrally formed with the support part 32. However, the support part 32 may have an attachment structure to which the concrete forming part 31 can be detachably attached as it is shown in Figure 6. The concrete forming part may be of various shapes. In particular, the detachable concrete forming part 31 allows for greater flexibility regarding the shape of the concrete elements to be fabricated. For example, the concrete forming part may have different heights for different concrete element thicknesses. Also, the angle of the chamfer may vary. It is even possible to provide complex geometries as grooves and protrusions depending on the retraction trajectory of the second portion. For example, the concrete forming part 31 might have a protrusion protecting to the front in an intermediate part thereof. Then, a pure horizontal retraction trajectory needs to be installed. In this way, a groove for a tongue-groove connection between concrete elements can be formed in concrete element 4. Similar, the concrete forming part 31 having a groove can form the tongue in concrete element 4, The concrete forming part 31 can then be easily attached to the support part at the retracted position.

The first and second portions 2 and 3 are preferably made of sheet metal, more preferably of metal, which is not ferromagnetic to avoid interaction with the magnetic unit The concrete forming part 31 can also be made of wood, for example.

It is further possible to dispense with the second chamfer strip 311 if no chamfer is desired at the upper side of the concrete element 4. Even then, the formwork apparatus is advantageous as removing of the concrete element 4 is facilitated. in the above embodiment, fixation of the first portion 2 on the formwork base 8 is performed by a magnetic force. However, it is possible to apply other fixation methods such as anchoring into or screwing to the formwork base.

In the above embodiment, holding of the second portion 3 at the work position is performed by the chocks 61 , which are fixable to the first portion 2 by screws 63 and nuts 62, As presented above, thereby holding takes place by absorbing of separation forces exceeding the biasing force. However, holding can also be performed by absorption of separation forces only, without a biasing force being applied. For example, a holding element might be provided which holds the second portion 3 at the position free from clearance and absorbs a separation force. When a biasing force is applied, it is preferable that the biasing force is applied via the first portion. Hence, a flux of force over the first portion 2 occurs which is fixed on the formwork base 8.

Another embodiment of a formwork apparatus 101 is shown in Figures 7 and 8. Figure 7 shows the formwork apparatus 101 with another example of a holding unit 106 in a non-holding state. Figure 8 shows the formwork apparatus 101 with the other example of the holding unit 106 in a holding state. The formwork apparatus 101 differs from the formwork apparatus 1 only in the configuration of the holding unit 106. The rest of the structure and operation of the formwork apparatus 106 is the same as in formwork apparatus 1. Hence, a detailed description thereof will be omitted.

Similar to the holding unit 6, also the holding unit 106 comprises a transferable member 1061 which is transferable between a holding state in which the second portion 3 is held at the work position and a non-holding state where the second portion 3 can be moved between the work position and the retracted position. While in the first embodiment, the chock was the transferable member 61 which is fixable (engageable) directly to the first portion 2, in the second embodiment, the transferable member is engageable with a receiving member 1062 which is fixed to the first portion 1.

That is, the transferable member 1061 is supported at the second portion 3 to be relatively movable thereto. It is preferred, as in the present case, that the transferable member 1061 is relatively displaceable with respect to the second portion 3 along the width direction of the formwork apparatus. The receiving member 1082 provided to the first portion 1 is a bushing and has an engaging portion 1063 » which is in the present case a through-hole and with which the transferable member 1061 is engaged in the holding state to hold the second portion 3 at the work position.

As can be seen in Figures 7 and 8 » the second portion 3 » in particular, the support part 32 is provided with a transferable member support portion 32c at a rear side of the vertical portion 32b. The transferable member support portion 32c supports the transferable member 1061 to be relatively movable with respect to the second portion 3. Here, the transferable member 1081 is supported by the transferable member support portion 32c to be relatively displaceable along the with direction and to be rotatable about a lengthwise direction of the transferable member 1081 which is about an axis parallel to the with direction. However, the transferable member 1061 might also be translationally displaced along other directions. The transferable member might also be rotated. For example, the transferable member might be a lever rotationally provided at the second portion which can be locked at the receiving member in the holding state.

As can be further seen from Figures 7 and 8 » the transferable member 1061 is provided with the handle 9. Here, the handle 9 is integrally formed with the transferable member 1061. The transferable member support portion 32c is further provided with a guide groove 1064 and a locking recess 1065.

Operation of the holding unit 106 will now be described.

In Figure 7, the second portion 3 is at the work position but in a non-holding state. An operator may grab the handle 9 which is supported at the second portion 3 via the transferable member support portion 32c. Thereby, the operator may pull backwards the second portion 3 to the retracted position for removing the concrete element 4.

At the work position, the operator may easily transfer the transferable member 1061 to the holding state. In Figure 7 » the handle 9 together with the transferable member 1061 is located at a right side (at a distance from the receiving member 1062). That is, the transferable member 1061 is not engaged with the engaging portion 1063 of the receiving member 1062. The operator may move the transferable member 1061 to approach the receiving member 1062. As can be understood from Figure 8, the operator moves the transferable member 1061 to the left side along an engaging direction (widthwise direction). During this movement, the displacement of the transferable member 1081 is guided by through-holes of the transferable member support portion 32c, preferably with sleeve bearings interposed between the transferable member support portion 32c and the transferable member 1061. Additionally, the handle 9 is guided by the guide groove 1064. Thereby, a smooth operation is ensured.

In the holding state, the transferable member 1061 is engaged with the engaging portion 1063 of the receiving member 1062. In other words, the transferable member 1061 is inserted into the through-hole 1063. In order to reliably maintain the transferable member 1061 at the holding state (in engagement with the receiving member 1062) the handle 9 and, hence, also the transferable member 1061 are rotated about the lengthwise axis of the transferable member 1061 by more or less 90°. Thereby, a portion 9a of the handle 9 is inserted into the locking recess 1065. The locking recess 1065 has a vertical recessed part 1065a which is vertically recessed and a horizontal recessed part 1065b. The horizontal recessed part 1065b is recessed from the vertical recessed part 1065a in a direction opposite to the engaging direction. Once, the portion 9a of the handle 9 is at the bottom of the vertical recessed part 1065a, the handle 9 and the transferable member 1061 is slightly moved to the right (opposite to the engaging direction) while maintaining a fully engaged state with the receiving member 1062. Thereby, the transferable member 1061 is reliably secured at the holding state. Even if during fabrication of the concrete element 4 vibrations occur, the transferable member 1061 is reliably prevented from coming out of the receiving member 1061.

In the above structure, the holding unit 106 comprises at least one transferable member 1061 which is transferable between a holding state and a non-holding state. At the holding state, the transferable member 1061 is coupled to the first portion 2 such that the second portion 3 is held at the work position at least partially via the transferable member 1061. That means that at least some flux of feree occurs over the transferable member 1061.

For this purpose, the transferable member 1061 is coupled to the first portion2 by the receiving member 1062, which is provided and fixed to the first portion 2 by screws. In the first embodiment, the transferable member 61 (chock) was pressed against the second portion 3 and then directly coupled to the first portion 2. The holding unit 106 has the advantage of easy operation as no additional tool is required. The operator can easily use the handle 9 for operation which is securely held by the locking recess 1065 in the holding state. Sn addition, atrition of the formwork apparatus 101 is reduced.

Please note that in the above configuration, the tip of the transferable member 1061 is preferably tapered which facilitates inserting Into the engaging portion 1063. Also, the transferable member 1061 is preferably a rotationally symmetric body, here a circular rod.

A clearance between the outer circumference of the transferable member 1061 and the engaging portion 1063 is preferably small in order to fabricate the concrete etement 4 with high accuracy. II should be further noted that the structure and form of the transferable member is not particularly limited. So, the transferable member might have a pinion portion which is to be engaged with a toothed rack as the engaging portion provided and fixed at the first portion. It is also possible to provide a conical tip to the transferable member such that the transferable member contacts the receiving member at the engaging portion (through-hole) along an outer circumference of the conical tip. Thereby, reliable contact without clearance between the engaging portion and the transferable member can be ensured. Then, the securing mechanism, for example, the locking recess above should elastically press the transferable member against the engaging portion to generate a biasing force.

It is further not necessary to hold the second portion 3 exclusively by a flux of force between the first portion 2 and the second portion 3. That is, the second portion 3 can be held partially by elements not coupled to the first portion 2 but, for example, coupling directly to the formwork base 8.

It should be noted that in the embodiments the second portion 3 is coupled to the first portion 2 such that the rotational degree of freedom around the joint axis is not locked when holding is not performed. That is, the holding unit 6 is applied to lock this degree of freedom by absorbing forces with a lever arm with respect to the joint axis. Thereby, the second portion 3 can be reliably held even if separation forces with components in the vertical and horizontal direction occur. However, it is possible that, for example, the first portion has a cam groove in which a bolt of the second portion is inserted and guided. Thereby, for example, the vertical or horizontal translation degree of freedom is not locked and need to be held at the work position via the first portion or another element. In other words, the degree of freedom, which is not locked while the second portion moves to the work position, needs to be locked at the work position. Of course, also several degrees of freedom might not be locked.

In the embodiments, the first chamfer strip 21 serves as a stop against which the second portion 3 abuts at the work position. However, a first chamfer strip 21 might not be required if no chamfer is desired at the lower side of the concrete element 4. For example, it might be desired to form a smooth vertical outer surface. In this case, it is preferable that the second portion 3 is biased into a direction towards the formwork base 8. Thereby, the lower side of the second portion 3 is pressed against the formwork base 8. Such bias might be established by a coil spring at the joint 7.

It is further possible to provide a bias force via a hydraulic unit. in case a smooth vertical outer surface of the concrete element is desired, a step might be provided in the formwork base. Then, the front side of the concrete forming part 31 (second portion 3) can be made to abut against the back side of the step. Similar applies if an insert bottom on which the concrete element is registered is attached to the formwork base. Here, the front side of the concrete forming part 31 can abut against the back side of the insert bottom.

In the embodiments, a surface contact occurs between the front side of the second portion 3 and the back side of the first chamfer strip 21. That is as a right angle is provided in the first chamfer strip 21. However, the angle between the second surface 21b and the third surface 21c might be greater than 90°. Then, an edge contact can be provided.

The configuration above wherein the first portion 2 is fixed to the formwork base 8 by a magnetic force is preferably applied to concrete forming parts with a height up to 100 mm. More preferably, the height is 70 mm.

For large heights, stronger magnets need to be provided as a larger fixation force is necessary to withstand the high pressures occurring during fabrication of concrete elements with large heights. However, using magnets providing larger forces impairs activation of the magnetic unit for transfer between the lowered and raised position. In particular, a simple upward linear movement of the activation unit is no longer possible without damaging the formwork apparatus. Rather, levers need to be used in order to lift the magnets from the lowered position.

This application also focuses on providing a magnetic unit, which can be easily transferred between a lowered and a raised position.

Reference is made to Figures 9 to 12.

The Figures 9 to 12 show such a magnetic unit 5. As can be seen from these Figures, the magnetic unit 5 comprises two magnetic packs 51 which are a pack of magnetic and ferromagnetic elements. The magnetic and ferromagnetic elements substantially extend parallel to each other along the horizontal direction.

At one inner end side, each magnetic pack 51 is pivotally supported at an activation device 12, in particular, at a central portion, which is a portion of a support unit 122 in the middle of the two magnetic packs 51. The support unit 122 extends substantially upright at a right angle to a ferromagnetic surface (the formwork base 8) in a vertical direction. The magnetic packs 51 are supported at a first support axis 51a which is a first support location. Here, the first support axis 51a is the same for both magnetic packs 51. Thereby, the magnetic unit 5 can be made compact and the number of parts can be reduced.

The activation device 12 further comprises a coupling unit 121 for pivoting the two magnetic packs 51 between a lowered position and a pivoted position. The lowered position is similar to the foresaid position, in which the magnetic packs 51 are in magnetic interaction with a ferromagnetic surface and is shown in Figures 9 and 10. The pivoted position is a position in which the magnetic interaction is reduced in comparison to the lowered position and is shown in Figure 11. The activation device 12 is configured to at least temporarily jointly pivot the magnetic packs 51 between the lowered position and the pivoted position.

For this purpose, the activation device 12 includes a coupling unit 121. The coupling unit 121 comprises a vertical rod 121a as a central load introduction portion, a horizontal bar 121b, and two nuts 121c. The horizontal bar 121b substantially transverses the vertical rod 121a. That is, the horizontal bar 121b extends substantially transversally along the horizontal direction. Each magnetic pack 51 is supported indirectly to the coupling unit 121 at respective second support axes 51b, which are second support locations. The magnetic packs 51 are supported by an intermediate element 121d to the horizontal bar 121b.

The distance between the first and second support axes 51a and 51b, which is a virtual connection between these axes defines a lever direction LD, as it is shown in Figure 10.

The coupling unit 121 is displaceable relative to the central portion of the support unit 122. For this reason, the vertical rod 121a is slidably supported by a sleeve bearing (not shown) within the support unit 122. The vertical rod 121a is displaceable relative to the support unit 122 along the vertical direction, which is a direction perpendicular to the formwork base 8 and is a relative displacement direction RD. In other words, the vertical rod 121a can be pulled away from the formwork base 8.

As can be seen from Figure 10, the lever direction LD and the relative displacement direction RD cross each other.

Operation of the magnetic unit 5 will now be described.

An operator may pull the activation device 12 upward away from the formwork base 8. In particular, he pulls the vertical rod 121a of the coupling unit 121. Thereby, the pulling force is transmitted via the two nuts 121c, which are screwed to the vertical rod 121a to the horizontal bar 121c.

At two opposite end sides of the horizontal bar 121b, the magnetic packs 51 are supported via the intermediate element 121d. They are supported such that the pulling force can be transmitted to them. If the pulling force is greater than the magnetic force and the gravity force of the magnetic packs 51 , each magnetic pack 51 begins to pivot around the first support axis 51a. That is, the pulling force is substantially oriented vertically (along an upward direction). As mentioned before, the coupling unit 121 is displaceable relative to the support unit 122 along the upward direction, which is the relative displacement direction RD. Hence, the support unit 122 cannot absorb force components pointing in the relative displacement direction RD. The magnetic packs 51 are supported at the support unit 122 at the first support axis 51a. As a force with a component along the relative displacement direction RD is received by the magnetic packs 51, respectively, at the second support axes 51b and acts with a lever arm with respect to the first support axis 51a and the magnetic packs 51 are supported at the first support axis 51a at the support unit 122, which cannot absorb the force with a component along the relative displacement direction RD, the resulting momentum initiates the pivoting movement of the magnetic packs 51. In other words, the coupling unit 121 pivots the two magnetic packs 51 jointly.

The pivoting movement is insured by the intermediate element 121d, which couples the magnetic pack 51 rotatably to the horizontal bar 121b. Thereby, the magnetic pack is allowed to move relative to the coupling unit 121 along a direction crossing the relative displacement direction RD. That is, the pivoting movement is a rotational movement with a component along the relative displacement direction RD and a component perpendicular thereto (a horizontal direction in Figures 10 to 12). If the magnetic pack 51 were fixed to the horizontal bar 121b without being allowed to move relative thereto along a direction crossing the relative displacement direction RD, the pivoting movement would be locked.

Figure 11 shows the magnetic packs 51 in a pivoted position. At the pivoted position, the relative displacement between the coupling unit 121 and the support unit 122 is stopped. That is, for example, the coupling unit 121 has a stop part, which abuts against the support unit 122. As mentioned above, the vertical rod 121a is slidably supported along the vertical direction in the central portion of the support unit 122 by a sleeve bearing. At a lower end side of the vertical rod 121a, the diameter of the vertical rod 121a might be increased to abut against a flat surface at a lower end side of the support unit 122 after certain relative displacement.

When the relative displacement is stopped, the coupling unit 121 and the support unit 122 are coupled together. Hence, the pivoting movement of the magnetic packs 51 is stopped. Preferably, they are coupled in the relative displacement direction RD. If then a further force along the relative displacement direction is exerted on the coupling unit 121, the entire activation device 12 moves translationally along the relative displacement direction RD. Thereby, the magnetic packs 51 are jointly displaced translationally along the relative displacement direction RD from the pivoted position, shown in Figure 11, to a raised position, shown in Figure 12. Hence, the activation device 12 is configured to jointly displace the magnetic packs translationally between the pivoted position and a raised position in which the magnetic interaction is further reduced in comparison to the pivoted position. Preferably, this translational movement coincides with the relative displacement direction.

With the magnetic unit 5, the magnetic interaction between the magnetic packs 51 and the ferromagnetic surface can be continuously reduced by the pivoting movement, wherein the required activation force is significantly lower in comparison to a case where the magnetic packs are removed from the ferromagnetic surface in a mere translational manner. Once, the magnetic packs 51 are sufficiently pivoted, translational removing operation can be performed with lower force.

As shown in Figures 9 to 12, the magnetic packs 51 are supported by the activation device 12 at respective end sides thereof in the extensional direction (horizontal direction). In particular, each magnetic pack 51 is supported at an inner end side close to the central portion of the support unit 122 at the first support axis 51a and at an outer peripheral side at the second support axes 51b. Thereby, a sufficient lever arm can be ensured and a sufficient momentum can be generated.

Furthermore, the activation device 12 has a central portion at which the magnetic packs 51 are supported. Thereby, the configuration can be made compact while ensuring a sufficient lever arm. It should be noted that here the entire support unit 122 constitutes a central portion between the magnetic packs 51. However, the configuration is not limited thereto. So, no central portion is required or only a portion of the support unit 122 extends centrally between the magnetic packs 51.

In addition, the activation device 12, in particular, the coupling unit 121 has the vertical rod 121a as the central load introduction portion. Thereby, the load can be easily introduced in a uniform manner, which facilitates operation. Additionally, the configuration can be made compact and easy. However, it is also possible to introduce a load eccentrically at two points, for example, or eccentrically at one point. However, at the later case, the operability is deteriorated as the magnetic packs 51 might not be pivoted at the same time and to the same extent

As can be seen from the Figures, the magnetic unit 5 is configured to be arranged symmetrically. For example, the magnetic packs 51 are arranged symmetrically with respect to a centre in which the support unit 122 is arranged. Also, the entire activation device 12 has a symmetric configuration. That is, the support of the magnetic packs 51 at the coupling unit 121 is symmetric with respect to the centre at which the central load introduction portion is arranged. Thereby, the operability is further enhanced. In particular, the pivoting movement of the magnetic packs 51 can occur at the same time and in a symmetric manner. Hence, the magnetic unit 5 can be moved away from the formwork base 8 along a predetermined trajectory.

It should be further noted that in the configuration of Figure 9 to 12 the support unit 122 has the central portion at which the magnetic packs 51 are pivotally supported. However, it might be also possible that the coupling unit 121 has a central portion at which the magnetic packs 51 are supported. Then, the support unit 122 might support the magnetic packs 51 at respective peripheral sides of the magnetic packs 51.

In the shown embodiment, two magnetic packs 51 are applied. However, it might be possible to use more magnetic packs, which are preferably arranged at equal intervals along a circumference around a centre. Thereby, the activation device 12 might have a substantially star shape.

In the embodiment, the activation device 12 is configured to move translationally. However, for example, a scissor mechanism might be applied for the coupling unit 121, at which the magnetic packs are supported, wherein the rotational movement of the scissor mechanism is transmitted to the magnetic packs.