Device for connecting structural form panels

A device is provided for connecting structural panels used to make pouring forms for concrete. It includes a connecting element dimensioned to fit between juxtaposed edge faces of adjacent form panels and having two sides one or both of which are provided adjacent the proximal edge faces of the panels with a longitudinal slot in which fasteners are engageable.

BACKGROUND OF THE INVENTION 
This invention is concerned with a device for connecting structural form 
panels, especially in the region of offsets of a structure, the form 
panels being of the type having at least at their margins webs or the like 
which are preferably provided with engagement portions for fastening 
means. 
A device of this type, for the connection of form panels in the region of 
building offsets, is already known from German allowed application No. 
1,902,568. The end faces of the form panels are formed by stiffening 
frames. Rails having mold parts corresponding to one another and fitting 
in one another, and which can also form a tension-resistant 
tongue-and-groove connection are secured to these endfaces. This 
connection permits the desired vertical displacement relative to one 
another of the nested mold parts, and consequently also of the form panels 
connected thereto. However, for this tension-resistant tongue-and-groove 
connection correspondingly expensive connecting parts are required which 
moveover, take up a relatively large part of the form face width. 
Furthermore, there is the risk that the mold parts which are plugged into 
one another may subsequently be detachable from one another only with 
difficulty, especially in the region of the plug connection, due to 
contamination which can frequently occur during concreting. 
SUMMARY OF THE INVENTION 
The object of the invention is therefore to provide a device of the 
above-mentioned type with which form panels offset in relation to one 
another can be fastened to one another, wherein the number of parts 
required is kept small and in which the release of the connection is not 
put at risk even in the event of contamination with concrete. While 
meeting these requirements, the storage requirements of the device are to 
remain as small as possible. 
To solve this problem, the device according to the invention has a 
connecting element which fits between the webs or similar elements of the 
form panels and is there fixable. This element has on at least one of its 
two sides, adjacent the end faces of the form panels to be connected, at 
least one longitudinal slot extending in its longitudinal direction and 
for serving the engagement of the fastening means. A form element is 
attachable or arranged on at least one face of the connecting element 
which is situated at right angles to the slotted sides. 
In this way a device is obtained with which even form panels which are 
offset in relation to one another, can be connected with a single 
connecting element and using the same fastening means otherwise used to 
connect form panels located adjacent to one another. Due to the use of the 
longitudinal slot a possibility for stepless adjustment is obtained. The 
connecting element can be relatively narrow and is easily introduced into 
a form, since it has itself a form skin. 
The width of the longitudinal slot corresponds approximately to the 
dimension of the fastening means for the connection of the webs or other 
elements and both side walls preferably each have a longitudinal slot to 
enable an offset of two form panels to be "distributed" to both sides of 
the connecting element. The spacing of the longitudinal slots from the 
margin of the connecting element adjacent the concrete can correspond to 
the spacing of the fastening locations on the webs or the like of the form 
panels from the form. This ensures that the form of the connecting element 
is aligned in functional position with the form of the adjoining form 
panels which are preferably arranged in a common plane. 
The width of the connecting element from the surface of the one slotted 
side wall to the other can corresponds approximately to a grid values of 
the wall thickness and preferably amount to about 5 or 6 cm. Due to the 
selection of such a value the fastening bolts extending from both sides 
have sufficient room on the inside of the connecting element even when 
they are located at the same height. Furthermore, a good adaptation to 
different standard values in the building trade is obtained. 
It is especially advantageous if the extension of the connecting element at 
right angles to the form, especially that of its slotted side walls, 
corresponds to the width of the webs or the like at the margin of the form 
panels. Due to this and due to the use of connecting bolts which have stop 
means in form of projections extending transversely to their elongation, a 
connection of the offset form panels can be effected without projecting 
parts extending from the rearside of the form wall, which can obstruct the 
arrangement of flanges, beams or the like. 
An especially advantageous feature is the fact that a single connecting 
element is sufficient and that it is not necessary to provide parts 
fitting into one another in a form-locking manner at the adjacent margins 
of the form panels which are to be offset in relation to one another. The 
fastening means already provided for the connection of the form panels, 
namely especially bolts with crosspins or optionally also with nuts or 
knock-in wedges, can allow a mutual vertical displacement in conjunction 
with the connecting element which is slotted on both sides. 
According to one embodiment of the invention it is possible also for that 
side of the connecting element which faces rearward in the functional 
position, to have an especially smoothly continuous closure optionally as 
second form skin. The element can then be used in any desired orientation; 
hence it can also be turned through 180.degree. about its longitudinal 
axis, which can simplify the installation and increase the life of the 
element. Especially with such a substantially closed connecting element it 
is advantageous to use fastening means in form of bolts which have at 
their free end projecting crosspins or similar stops which can fit through 
keyhole-like perforations and be locked by turning. 
The above-mentioned optional installation of the element is favoured if the 
longitudinal slots are situated in the middle of the side walls of the 
connecting element. This is of advantage when a single such longitudinal 
slot is provided. Several parallel longitudinal slots could optionally be 
provided, if parallel rows of perforations for the mutual fastening are 
provided on the form panels. 
The device according to the invention allows effective cleaning by access 
through the longitudinal slots even with a closed form of construction. Of 
only one side is closed by a form skin, the cleaning possibility is even 
better. A further substantial advantage, especially of the connecting 
element, consists in that it can also be fastened in the same way on 
horizontal margins of corresponding form panels, and e.g., transverse form 
panels which then no longer correspond in their width extension to the 
subjacent form panels can then also be connected. If the connecting 
element has clamping points, the form panels arranged on both sides 
thereof can be braced thereby. 
Furthermore, a substantial advantage of the connecting element is that it 
can overlap form-panel butt joints extending transversely to its 
elongation so that it offers an additional reinforcing effect for the 
entire form. This can be utilized both with a vertical and with a 
horizontal arrangement of the connecting element for joints extending 
respectively horizontally or vertically. The element thus performs the 
function of an additional beam or of a flange without projecting beyond 
the outline of the form panels. For this reinforcing effect the connecting 
elements are, along the elongation of the form, either offset as a whole 
in relation to the form panels or are provided in correspondingly modified 
lengths, so that they can intersect and overlap the form-panel butt joints 
extending transversely to their elongation. Form corners can also be 
connected to form panels and may be optionally offset relative to the 
same. 
The novel features which are considered as characteristic for the invention 
are set forth in particular in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of specific embodiments when read in 
connection with the accompanying drawing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A device for the connection of form panels which can be offset in relation 
to one another in one or another form, as illustrated in FIG. 3 by way of 
a vertical offset and in FIG. 4 by way of an offset in respect of the 
dimensions of the form panels, has a connecting element 1 (FIG. 1) which 
fits between the webs 2a forming the end faces of the form panels 2. This 
connecting element 1 is provided on its two side walls 3 adjacent the end 
faces of the form panels 2 to be connected, with longitudinal slots 4 
extending in its longitudinal direction and serving for the engagement of 
fastening means; it also has a form skin 5 on a face situated at right 
angles to the slotted side walls 3. In the examplary embodiment the 
fastening means are bolts 6 with stop projections 7 which are arranged 
transversely to the bolt elongation and which can be pushed through 
keyhole-like perforations in the webs 2a and then be locked by turning of 
the bolts. In the inserted position they also fit through the longitudinal 
slots 4, while in the turned position they grip above the margins of the 
longitudinal slots 4 from behind with their stop projections 7 (FIG. 2). 
The width of the longitudinal slots 4 is selected to correspond to the 
diameter of the bolts 6. 
The spacing of the longitudinal slots 4 from the margin 8 of the connecting 
element 1 adjacent the concrete corresponds to the spacing of the 
fastening location or of the perforation for the bolt 6 on the webs 2a for 
the form panel 2, from the form skin 9 thereof. FIG. 2 shows that in the 
function position the form skin 5 of connecting element 1 is aligned with 
the form skin 9 of the adjoining form panels 2 which in one plane in the 
exemplary embodiments according to FIGS. 3 and 4, are located in a common 
plane. Form corners, form-removing devices or the like can optionally also 
be connected. 
The width of the connecting element 1 from the surface of the one slotted 
side wall 3 to the other corresponds appropriately to a grid value of wall 
thickness and amounts preferably to about 5 or 6 cm. 
The extension of the connecting element 1 at right angles to the form skin 
5, especially that of its slotted side walls 3, corresponds in the 
exemplary embodiment to the width of the webs 2a at the margin of the form 
panels 2. When these connecting elements 1 are used this results in a 
smooth form wall not only on the side adjacent the concrete, but also on 
the rearside remote therefrom. Also, the fastening means, i.e., here the 
bolts 6, do not project beyond the outline of the form at the rear, since 
they disappear in the reinforcement thereof. 
In the exemplary embodiment the longitudinal slots 4 are each situated in 
the middle of the side walls 3 of the connecting element 1. This is 
appropriate for form panels where the perforations for the fastening means 
6 are likewise arranged in the middle of the webs 2a. If these 
perforations are arranged eccentrically, however, then the longitudinal 
slots 4 must also be arranged correspondingly. 
The exemplary embodiment provides in an especially simple and effective way 
for a longitudinal slot 4 to be continuous from bottom to top of the 
element 1, especially on each of the two sides of the connecting element 
1. There could optionally also be provided several longitudinal slots 
which are aligned with one another, but are interrupted by intermediate 
webs in order to increase the stability of the connecting element 1. 
However, a fastening element 6 could not then be used at the points where 
these longitudinal slots would be interrupted. The use of a continuous 
longitudinal slot 4 according to the exemplary embodiment is therefore 
especially advantageous for a stepless adjustment and to permit arbitrary 
offsetting of form panels to be connected to one another. 
In the exemplary embodiment the inside of the substantially hollow 
connecting element 1 is provided with reinforcing plates 10 which are 
arranged transversely to its longitudinal extension and which, if the 
connecting element 1 is made from metal or sheet-metal strips, can be 
stiffening elements for it. In such a case the element 1 may be 
manufactured by welding in the region of the longitudinal slots 4 these 
reinforcing plates 10 each having a cutaway 11 whose contour corresponds 
at least to the projection of that part of the connecting bolt 6 or of 
another fastening means which extends into the connecting element 1. This 
arrangement can be seen in FIG. 2 where the cutaway 11 is rather larger 
than the part projecting therein of the bolt 6 with its stop projection 7. 
Such bolts 6 thereby fit also directly into the longitudinal slots 4 in 
the region of the reinforcing plates 10. 
It is especially advantageous if the connecting element 1 has clamping 
points so that the form panels 2 connected to it can be braced, together 
with this connecting element 1 or via this connecting element 1. In this 
connection it is especially advantageous if the connecting element 1 has 
on at least one side face 3 at least one marginal cutaway 12 extending 
thereover and in addition thereto or in lieu thereof, at least one 
perforation 13 (see especially FIG. 2) in its form skin 5 and serving as 
clamping point; the rear side of the connecting element 1 remote from the 
concrete is then preferably open. If this rear side is closed, it likewise 
has opposite the perforation 13 a passage for a clamping element. The open 
rear side also allows a somewhat oblique arrangement of a form tie rod 
which extends through the perforation 13. 
The embodiment of FIG. 3 shows that several clamping points can be arranged 
next to one another in the lower region of the connecting element 1, such 
clamping points being formed by at least one perforation 13 in the form 
skin 5 and at least one marginal cutaway 12 located especially at the same 
height on one side face. In the exemplary embodiment even two such 
marginal cutaway 12 may be provided, located at the same height. These 
cutaways 12 are arranged in the one end region and have an approximately 
semi-circular cross-section which together with a corresponding marginal 
cutaway 14 of an adjoining form panel 1 located in a correspondingly 
matching position, forms a round clamping point for a form tie rod as 
suggested in the left part of FIG. 3 where a form tie rod 15 is shown in 
dot-and-dash line. In the right part of FIG. 3 the marginal cutaways 14 of 
the form panels do not fit together with the marginal cutaways 12 of the 
connecting element, so that the perforation 13 can be utilized there to 
introduce a form tie rod 15. 
FIGS. 1 and 3 also show that a preferably quadrant-shaped marginal cutaway 
17 is provided at one end of the connecting element 1, in this case at the 
upper end, in the transitional region of the side faces 3 to the end face 
16 on at least one side, but in the exemplary embodiment again on both 
sides. The radius of curvature of cutaway 17 corresponds, as with the 
semi-circular marginal cutaways, approximately to the radius of a form tie 
rod 15. The left part of FIG. 3 shows that a connection to a 
correspondingly shaped form panel 2 which has in its corner region 
likewise a quadrant-shaped marginal cutaway 18, establishes a 
semi-circular cutaway which can be completed with corresponding further 
cutaways to form a clamping point. In this end region near the 
quadrant-shaped marginal cutaways 17, a perforation 13 is provided which 
acts as clamping point and passes through the form skin 5 of a connecting 
element 1. This perforation can be used when a vertical offset of the 
connecting element 1 is effected, as illustrated in the right part of FIG. 
3, whereby the quadrant-shaped marginal cutaways 17 are therefore not 
completed to form a clamping point, but the arrangement of a form tie rod 
15 is appropriate in this end region of the connecting element 1. 
Primarily when a larger vertical offset is desired, it is advisable if the 
connecting element 1 extends over an equally large portion of the length 
of the form panels adjacent one another, but offset vertically in relation 
to one another. 
The clamping points on the connecting element 1 have the considerable 
advantage that the clamping forces can be transmitted from them to the 
directly connected form panels, so that it may be possible to save 
clamping points. 
FIG. 1 also shows that in the region of the clamping areas provided on the 
connecting element 1, the reinforcing metal sheets 10 arranged around them 
also serve as bearings for the tightening nuts on the rear side of the 
connecting element 1, i.e., the side remote from the concrete. It is shown 
clearly that in the regions where such clamping areas 12 or 17 and 13 are 
provided, the reinforcing plates 10 are arranged closer to one another or, 
in the upper region, closer to the upper closure plate 16. This increases 
the stability of these clamping areas and provides a good bearing for the 
nuts which are screwed onto the form tie rods. 
In the exemplary embodiment the connecting element 1 is welded together 
from sheet-metal strips and the side walls 3 may each be optionally formed 
from two strips which are parallel in the longitudinal direction and are 
aligned with one another with their surfaces and leave the longitudinal 
slot 4 free between them. Further advantageous applications of the 
invention are illustrated in FIG. 4. This Figure shows a vertical 
connecting element 1 which extends over a larger height than the 
individual form panels 2. It therefore overlaps or bridges the horizontal 
joint 19 between the form panels 2 standing on one another. This region is 
thereby better reinforced, so that the connecting element 1 can also 
fulfil the function of an additional beam due to its additional 
reinforcing effect. 
Furthermore, FIG. 4 shows how such connecting elements 1 can, due to a 
horizontal arrangement, bridge and reinforce the vertical points 20 
between form panels 2 standing next to one another. It is also illustrated 
that this permits securing, at a level above form panels of equal size 
further form panels 21 which differ in their dimensions. It is seen in 
FIG. 4 how two transverse rectangular form panels are attached, which are 
larger in their horizontal longitudinal extension than the width of the 
form panels situated thereunder. Here, also, an offset of the form panels 
and their margins in relation to one another is obtained, but this offset 
is bridged by the connecting element 1. The connecting elements 1 can have 
different lengths, to be adapted to different form panel dimensions. 
However, since they can abut one another directly, the desired purpose can 
be achieved with a single length. An additional advantage of such a 
horizontal arrangement of the connecting elements 1 continuing one another 
consists in that a good reinforcement is also obtained in the region of 
joints 20 abutting these parts perpendicularly, so that this arrangement 
can fulfil at least partly the additional purpose of a flange. It is 
advantageous, both in the case of a horizontal and also in the case of a 
vertical arrangement of these connecting elements 1, that these parts do 
not project beyond the outline of the form and can be connected with the 
same fastening elements with which the form panels 2 can otherwise be 
fastened to one another, so that these fastening elements, do not project 
from the rear side of the form panels. They therefore represent no 
obstruction for any additionally necessary beams, flanges, brackets and 
similar parts to be connected to the rear side of form wall. 
All in all, owning to the connecting element according to the invention, 
there can be achieved a vertical offset or another offset of form panels 
or a bridging of form joints for the purpose of a reinforcement with a 
single part which can even be connected with those fastening means that 
otherwise serve to connect the form panels themselves to one another. 
Still another advantage resides in the fact that by means of the bolts 6 
and the stop projections 7, as well as a correspondingly sized 
intermediate space between the top projections 7 and the head 6a of the 
bolt, or by means of an interposed cup spring 6b, such a large clamping 
force can be generated that the parts can be connected to one another 
sufficiently firmly to remain in the set position. Additional measures to 
fix the selected vertical offset can therefore be omitted. 
The open form of construction shown in FIG. 1 of the connecting element 1 
facilitates cleaning thereof and, when the perforations 13 are used for 
form tie rods, also allows an inclined orientation thereof in relation to 
a perpendicular line to the form skin 5, due to which an improved 
adaptability of the entire form and a compensation of tolerances at 
clamping areas e.g., not situation exactly opposite one another, are 
possible. 
Altogether, there is obtained a simple to handle device with which it is 
possible to connect form panels which are vertically offset in relation to 
one another or which do not match one another in respect of their length 
dimensions or the arrangement of their fastening points. Moreover, a 
stepless adjustment of arbitrary displacements is possible and form panels 
matching one another in their dimensions can be reinforced additionally in 
a form wall by means of this device. Besides the use of the 
above-described bolts, which are also suitable for connecting the form 
panels to one another, other fastening means can be provided, such as 
bolts with nuts, with wedges or the like, although it is always preferable 
to use those connecting means which are also otherwise provided in 
relation to the form. Finally, it should also be mentioned that instead of 
form tie rods provided with nuts it is also possible to provide the same 
with wedges, the reinforcing plates 10 in the region of the clamping 
points being advantageous under these circumstances too, since they can 
form a bearing for a wedge, also. 
In a modified form of construction, or as a supplement to the 
above-described form of construction, the rear side of the connecting 
element 1 remote from the form skin 5 can have a closure which has 
fastening areas for the fastening means, especially keyhole-like 
perforations, or at least a longitudinal slot with a width corresponding 
to the diameter of connecting bolts 6 or the like. The connecting element 
can thereby be used also as a corner piece or for a rectangular 
termination of a form skin. When a longitudinal slot is employed, a 
vertical offset is then possible as well. This can be appropriate 
primarily with a horizontal arrangement of the element at the upper margin 
of a form, when a cantilever is to be sheathed there. Even one of the side 
walls could optionally be completely closed or closable in order to be 
able to form an inner corner. 
Contrary to the above-described exemplary embodiment one of the side walls 
3, preferably one situated opposite the longitudinal slot 4 of the other 
side wall 3, can have at least one row of astening perforations for the 
fastening means, such as connecting bolts 6. A longitudinal slot is then 
always available for a vertical offset, and a jump in the vertical offset 
of the element from perforation to perforation is also possible. If the 
hole spacings are selected correspondingly, these jumps will be relatively 
small, so that a sufficiently good bridging of a vertical offset is 
possible due to the stepless adjustability at the longitudinal slot. 
While the invention has been illustrated and described as embodied in an 
arrangement for connecting form panels, it is not intended to be limited 
to the details shown, since various modifications and structural changes 
may be made without departing in any way from the spirit of the present 
invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention.