Turnbuckle for Tensioning Frame Formwork Elements

The present application claims the priority of German patent application 10 2022 107 429.3, the content of which is fully incorporated herein by reference thereto.

The invention relates to a turnbuckle for tensioning frame formwork elements according to the preamble of claim.

A generic frame turnbuckle is known from WO 2005/007997 A1.

Frame formwork elements are used to erect boundaries for bodies to be cast, in particular concrete bodies such as building parts. In order to obtain castable boundaries, a plurality of frame formwork elements must generally be fixedly connected or tensioned with one another. Turnbuckles that are also known as alignment couplers or assembly locks are used to tension the frame formwork elements.

In general, turnbuckles are used to connect adjoining frame formwork elements to one another in a flush, aligned and tight manner. Turnbuckles are used in particular to connect or tension two adjoining frame formwork elements to one another, wherein inner corners, outer corners, articulated corners and face formwork can also be connected by means of the turnbuckles.

The turnbuckles can also be used to connect a frame formwork element to an adjoining compensating element. Compensating elements are used to provide length compensation and are typically arranged between two conventional frame formwork elements. The compensating elements are usually made of wood, steel or aluminum.

Conventional frame formwork elements have a circumferential frame having at least two vertical frame elements and two horizontal frame elements as well as horizontal struts for stabilizing the frame. The struts generally extend horizontally between the two vertical frame elements of the frame. In addition, vertical struts can also be provided to further stabilize the frame. Compensating elements can have a different structure, but a circumferential frame is generally also provided in this case.

A formlining is or can be attached to the frame in a known manner.

Compensating elements also constitute frame formwork elements in the context of the present invention.

Turnbuckles are generally arranged in the region of the intersections of horizontally extending struts and vertically extending frame elements of the frame. In each case, one clamping jaw of the turnbuckle engages around a portion of a vertically extending frame element of two frame formwork elements to be connected. By means of a wedge, the two clamping jaws and thus the frame formwork elements are then tensioned against one another, i.e. the clamping jaws are moved towards one another.

The turnbuckle generally has a crossmember and a first clamping jaw which is typically connected immovably to the crossmember. Furthermore, the turnbuckle has a second clamping jaw, wherein the second clamping jaw can be shifted in a bracing direction along the longitudinal axis of the crossmember towards the first clamping jaw in order to tension the frame formwork elements.

The clamping jaws preferably each have two claws, wherein the two claws of a clamping jaw have a distance from one another such that a horizontally extending strut can be accommodated between the two claws.

Such clamping jaws are also referred to as lugs.

In the turnbuckles known from the prior art, it is usually provided that the direction of translation of the wedge when it is driven into the turnbuckle during bracing (hereinafter also referred to as the wedge-driving direction) or when releasing the wedge and the clamping direction, i.e. the movement of the second clamping device along the crossmember, are at right angles to one another. If two horizontally adjacent frame formwork elements are connected in a conventional manner to such a turnbuckle, i.e. tensioned horizontally, gravity acts fully on the wedge in such a way that it is pulled in the direction of greater tensioning. This has been found to be advantageous.

In order to tension boundary surfaces of two adjacent frame formwork elements which experience particularly large forces, for example in articulated corners or outer corners, several turnbuckles are used adjacent to one another. The turnbuckles are then typically arranged on a straight line, e.g. one below the other, i.e. vertically offset from one another, with parallel tensioning movements of the clamping jaws in each case.

However, this arrangement can cause the wedges of the individual turnbuckles to obstruct one another. Furthermore, care must be taken to maintain a sufficient distance between the wedge ends, which are driven in and released by means of hammers, and any kind of obstruction so that said wedges may be operated by means of a hammer without interference.

A further disadvantage of the aforementioned turnbuckles is that they generally cannot be mounted on the lowest strut, since there is not enough space there. The wedge requires space below the crossmember, into the toothed portion of which the wedge is to be driven, such that the wedge can project below the crossmember. After the wedge has been driven in, there must also still be enough space to be able to loosen the wedge again by hammer blows in the opposite direction.

An important requirement for turnbuckles further consists in that they should be suitable for connecting frame formwork elements whose frames have different thicknesses, for example depending on whether outer corners, articulated corners or the like are to be connected. For this purpose, it is advantageous if the turnbuckle has a quick adjustment feature so that the distance between the two clamping jaws of the turnbuckle can be quickly and easily set to the desired dimension, the turnbuckle attached and then the frame formwork elements tensioned. The turnbuckles should thus have a suitable span that can be adjusted quickly. At the same time, however, it is also required that large forces can be applied briefly, so that the turnbuckle, when attached to two frame formwork elements, can reliably fix or tension them. The aforementioned turnbuckles, which are tensioned with a combination of hammer and wedge, have proven to be suitable for this purpose.

Turnbuckles that can be operated without striking aids are also known from the prior art. In this case, length adjustment by means of a spindle is known, but this does not allow quick adjustment.

In practice, turnbuckles have become established in which the two clamping jaws, as described above, can be moved towards one another and tensioned together by means of a wedge driven in by a striking tool. Such turnbuckles have become established since these turnbuckles on the one hand ensure a flush, aligned and tight connection between frame formwork elements, and on the other hand such turnbuckles enable quick adjustment in order to adjust the turnbuckles to different spans between the frames of the frame formwork elements to be connected.

Such a turnbuckle is disclosed in the generic document. The generic document states that the direction with which the wedge is driven into the turnbuckle and the bracing direction form an angle α<90° to improve operation of the wedge. Typically, however, the angle in such turnbuckles is α=90°.

The object of the present invention is that of improving the previously known prior art, in particular to provide a turnbuckle for bracing frame formwork elements, which can be released quickly and easily even in installation situations that are difficult to access.

This object is achieved by the features of claim.

The turnbuckle according to the invention for bracing frame formwork elements comprises a first clamping device having a crossmember and a first clamping jaw. The crossmember has a toothed portion comprising a row of track teeth arranged one behind the other and extending in parallel with one another. Furthermore, a second clamping device comprising a second clamping jaw and a guide device is provided. The second clamping device can move in a bracing direction along the crossmember toward the first clamping jaw. The turnbuckle further comprises a wedge which, guided by the guide device, can move along a wedge-driving direction and can be brought into engagement with at least one of the track teeth in order to fix the two clamping devices in a bracing position.

According to the invention, it is provided that the guide devices have a cross brace that can move transversely to the wedge-driving direction between an unlocking position and a locking position. The cross brace is designed and arranged such that, in the locking position, the cross brace limits a stroke of the wedge in a direction orthogonal to the toothed portion such that the wedge can be brought into engagement with the at least one track tooth in the bracing position, and wherein the cross brace enables a larger stroke of the wedge in the unlocking position.

Since the turnbuckle according to the invention has a cross brace, the movement of which between an unlocking position and a locking position can influence a stroke performable by the wedge in a direction orthogonal to the toothed portion, when the turnbuckle according to the invention is bracing two frame formwork elements with one another, i.e. is in the bracing position, it can be released in a simple manner even if the turnbuckle is mounted in a constrained position in which the wedge cannot be released again by hammer blows counter to the wedge-driving direction. Such a constrained position can occur, for example, in frame formwork elements where the turnbuckle is fixed to a lower horizontal strut or when a plurality of turnbuckles are mounted one above the other in a straight line with little spacing. A constrained position in which the wedge cannot be released again by hammer blows opposite the wedge-driving direction or cannot be easily released again by hammer blows opposite the wedge-driving direction can also arise in particular in frame formwork elements which form foundation formwork, or in frame formwork elements which have only a small vertical height, for example frame formwork elements which are used to construct foundations, e.g. train paths.

The turnbuckle according to the invention is particularly suitable for frame formwork elements that are used to produce wall formwork.

The solution according to the invention makes it possible not to have to actuate the wedge in order to re-release the turnbuckle from the bracing position. Release is easy using the cross brace. This allows the wedge to fall out of the bracing position or be removed without requiring any expenditure of force.

The turnbuckle according to the invention, in particular also the cross brace, can be simply and quickly operated to release the two clamping devices when they are fixed with respect to one another in a bracing position. No additional tool is required to operate the cross brace. Manual operation or, if necessary, operation using the available tool, in particular a hammer, is sufficient to move the cross brace, in particular to move it from a locking position to an unlocking position.

In order to fix the clamping device in a bracing position, it can be provided that the cross brace is first moved into the locking position in such a way that the cross brace limits a stroke of the wedge in a direction orthogonal to the toothed portion such that the wedge can be brought into engagement with the at least one, preferably two, track teeth in the bracing position. For this purpose, the wedge can be driven into the toothed portion in a known manner, preferably using a hammer. The wedge is moved in the wedge-driving direction. Operation of the turnbuckle, in particular to fix the two clamping devices or the two clamping jaws with respect to one another in a bracing position by means of the wedge, can be carried out in a known manner. In order to release the fixation of the two clamping devices from the bracing position, it can then be provided that the wedge is released again from the toothed portion in the opposite direction, i.e. opposite to the wedge-driving direction, by hammer blows. Alternatively, particularly when there is a constrained position, the clamping device can, according to the invention, also be released from the bracing position by moving the cross brace from its locking position in which it limits the stroke of the wedge in a direction orthogonal to the toothed portion such that the wedge engages with at least one of the track teeth in the bracing position, into an unlocking position in which the cross brace enables a greater stroke of the wedge. Since the cross brace allows for a greater stroke of the wedge in a direction orthogonal to the toothed portion, i.e. because the wedge can move further away from the toothed portion in an orthogonal direction, the toothed engagement between the wedge and the track tooth or the particular track teeth of the toothed portion is at least loosened. The wedge can thus be moved out of the toothed portion without the need for hammer blows or a greater amount of effort.

The stroke of the wedge in a direction orthogonal to the toothed engagement is also orthogonal to the longitudinal axis of the wedge or to the wedge-driving direction.

In the unlocking position, it is advantageous for the cross brace to allow a stroke of the wedge in such a way that engagement of the wedge in the track teeth is at least reduced in the bracing position.

To release the turnbuckle, it can be sufficient for the cross brace to at least reduce the engagement of the wedge in the track teeth in the unlocking position. This can, for example, mean that the wedge can be loosened without the need for hammer blows.

It is advantageous if the cross brace increases the stroke of the wedge in the unlocking position such that the wedge can be disengaged from the track teeth in the bracing position.

One design of the cross brace whereby, in the unlocking position, the stroke of the wedge is increased to such an extent that the wedge does not engage with the track teeth in the bracing position has proven to be particularly suitable. This allows the fixation of the clamping devices to be released even if the wedge is not moved against the driving-in movement or in the opposite direction to the wedge-driving direction.

The turnbuckle according to the invention thus makes it possible to release the fixation of the turnbuckle in a position in which it tensions two frame formwork elements with one another in two different ways, on the one hand by axially moving the wedge counter to the wedge-driving direction by means of hammer blows and, on the other hand, by moving or passing the cross brace from a locking position to an unlocking position.

It is advantageous if the cross brace interacts with the wedge in such a way that, depending on the position of the cross brace, the cross brace acts on the wedge such that a stroke of the wedge is mechanically limited, preferably by direct contact between the wedge and the cross brace or by means of an intermediate element or a plurality of intermediate elements, for example a wedge contact rail (described in more detail below).

It is advantageous if the wedge limits a stroke of the wedge in the locking position in such a way that, when it is driven into the toothed portion up to the bracing position, the wedge cannot perform a stroke, i.e. the stroke is zero in the bracing position. By moving the cross brace from its locking position to the unlocking position, the stroke is increased, i.e. a stroke is set that is greater than the stroke that the wedge can assume when the cross brace is in the locking position.

It may be provided that the stroke of the wedge which it can assume corresponds to a value which is greater than 10% of amount of the tooth depth of the track teeth when the cross brace is in the unlocking position. The tooth depth is understood to mean the distance between the tip of the track teeth and the valley of the track teeth, or the head of a track tooth and the foot of a track tooth. More preferably, the stroke is at least 20%, even more preferably at least 30%, in particular at least 50%, of the tooth depth. Very particularly, it can be suitable if the stroke is the same size, in particular larger, than the teeth depth such that the teeth of the wedge, which are in engagement with at least one of the track teeth, can be completely disengaged from the track teeth when the wedge is driven into the bracing position.

It is advantageous if the stroke that the wedge can assume is less than twice the tooth depth, preferably less than 150%, in particular less than 120%, of the tooth depth when the cross brace is in the unlocking position.

The stroke of the wedge is understood to mean the movement of the wedge orthogonally to the toothed portion in a direction leading away from the toothed portion. If the stroke is zero, which is preferably the case when the wedge is driven into a bracing position such that the two clamping devices are fixed with respect to one another, the wedge is not movable in a direction orthogonal to the toothed portion.

It is advantageous if the cross brace can move parallel to the bracing direction between an unlocking position and a locking position.

Movement of the cross brace parallel to the bracing direction has proven to be particularly suitable for influencing, by the movement of the cross brace, a stroke which the wedge can perform in a direction orthogonal to the bracing portion.

It is advantageous if the guide device has a housing part with at least two guide recesses which are arranged at a distance from one another in the wedge-driving direction and through which the wedge is passed, wherein the guide recesses guide the wedge in the wedge-driving direction, and wherein the cross brace is arranged on the housing part so as to be movable transversely to the wedge-driving direction.

Since the guide device has a housing part with at least two guide recesses through which the wedge is passed, the wedge can be moved in a particularly advantageous manner in the wedge-driving direction, in particular brought or driven into a bracing position, such that the wedge or the teeth of the wedge is/are brought into engagement with one of the track teeth in such a way that the two clamping devices or the two clamping jaws are fixed with respect to one another. It has proven to be particularly suitable in this regard if the cross brace is moveably arranged on the housing part transversely to the wedge-driving direction. Such an arrangement can be realized in a particularly stable and reliable manner. This is particularly advantageous for robust use and with regard to the requirements on construction sites.

According to the invention, it can be provided that the housing part and/or the cross brace have a U-shaped profile in cross section.

It has proven to be advantageous if the housing part and the cross brace have an at least approximately U-shaped profile in cross section.

It can be advantageous if the cross brace is fixed to the inside of the housing part.

It is also advantageous if the cross brace, which is preferably U-shaped in cross section, is arranged in the housing part, also preferably U-shaped in cross section, in such a way that the housing part and the cross brace are identically oriented, preferably in such a way that a longitudinal axis of the cross brace and a longitudinal axis of the housing part run transversely to the wedge-driving direction. The longitudinal axes extend along the bottom of the respective U-shaped profile from a front end to a rear end of the cross brace or the housing part such that the longitudinal axes extend centrally between the side walls of the U-shaped profile on the bottom.

The housing part and the guide device are preferably formed integrally with the second clamping device. The two side walls of the second clamping jaw are preferably integrally connected to a side wall of the U-shaped profile of the housing part and extend in a direction that faces away from the bottom of the U-shaped profile of the housing part. Alternatively, however, the second clamping jaw can also be connected to the guide device and the housing part in another way, in particular integrally or in a force-fit, for example welded or screwed.