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Title:
A DEVICE FOR FORMWORK CARTRIDGES
Document Type and Number:
WIPO Patent Application WO/1996/008621
Kind Code:
A1
Abstract:
A formwork cartridge (10a) which, together with further identical formwork cartridges (10b, 10c and so forth), besides a formwork plate (23a), comprise a framework consisting of two parallel uprights (11a) connected through intermediate, lateral transoms (12a), wherein the outer end faces (12a') of the transoms (12a) rest against the neighbouring side face (11a') of the adjacent upright (11a), and wherein the connection between uprights and transoms is established in the areas of said faces (12a' and 11a') resting against each other, by means of fixing means such as nails, fishiing plates (13a) and/or similar fixing means. In order to establish a strong connection between uprights and transoms, requiring a minimum of securing measures to be taken by means of said fixing means, said end faces (12a') of the transoms (12a) and said side faces (11a') of the uprights (11a), said side faces resting against the transom end faces, are chamfered such that they slope forming an acute angle with imaginary vertical planes (II-II) perpendicular to respective formwork plate (23a). The strengthening of the connections between uprights (11a) and transoms (12a) enables a reduction in upright and transom dimensions, maintening the same strength properties as known formwork cartridges having the same external measures.

Inventors:
BERLAND LEIF (NO)
Application Number:
PCT/NO1995/000160
Publication Date:
March 21, 1996
Filing Date:
September 11, 1995
Export Citation:
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Assignee:
BERLAND LEIF (NO)
International Classes:
E04G9/04; E04G11/10; E04G17/02; E04G17/04; (IPC1-7): E04G9/04; E04G11/14; E04G17/04
Foreign References:
US5159893A1992-11-03
DE4224726A11994-02-03
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Claims:
C l a i m s
1. A device for a formwork cartridge (10a, 10b, 10c) which, besides a formwork plate (23a, 23b, 23c) , comprises a framework consisting of two parallel uprights (lla, lib, lie) connected through intermediate, lateral transoms (12a, 12b, 12c), wherein the outer end faces (12a1, 12b', 12c') of the transoms (12a, 12b, 12c) rest against adjacent side faces (lla', lib', lie') of neighbouring uprights (lla, lib, lie) , and wherein the connection between uprights and transoms is established in the areas of said faces (12a', 12b', 12c' and lla', lib', lie') resting against each other by means of fixing means such as nails, fishing plates (13a, 13b, 13c) and/or similar fixing means, c h a r a c t e r i z e d i n that the end faces (12a' , 12b', 12c') of the transoms (12a, 12b, 12c) and said side faces (lla', lib', lie') of the uprights (lla, lib, lie) resting against the transom end faces slope, forming an acute angle with an imaginary vertical plane (IIII) perpendicular to respective formwork plate (23a, 23b, 23c) .
2. A device as set forth in claim 1, c h a r a c t e r i z e d i n that the spacing of the transoms (12a, 12b, 12c) increases gradually in a direction upwardly, from below.
3. A device as set forth in claim 1 or 2, c h a r a c t e r i z e d i n that at least some (12a) of the transoms have a trapezoidal crosssection, where the longest parallel side of the trapezium is spaced from the formwork plate (23a, 23b, 23c) , extending parallel thereto.
4. A cartridge formwork comprising a number of formwork cartridges (10a, 10b, 10c) designed and shaped in accordance with claim 1, 2 or 3, as well as a number of interconnecting stays (14) extending laterally in relation to the course of the two formwork sides, said stays (14) , upon the attachment thereof to two formwork sides, serve to secure the spacing of the formwork sides and to keep these together when the load from the concrete occurs, said lateral interconnecting stays (14) each having a hole at each end to cooperate with a interconnecting means (15) securing the relative positions of each interconnecting stay (14) and two neighbouring uprights (lla, lib respectively lib, lie) each belonging to a formwork cartridge of its own, c h a r a c t e r i z e d i n that the interconnecting means (15) consists of a double hoopshaped thread having two free end branches (16, 17) connected to each other through angled intermediate branch portions (2022) and each lying in a vertical plane perpendicular to the other.
5. A cartridge formwork as set forth in claim 4, c h a r a c t e r i z e d i n that one free end branch (17) of the interconnecting means (15) merges into a first intermediate branch portion (20) which, preferably, extends parallel to the other free end branch (16) and which merges into a second intermediate branch portion (21) which, preferably, extends parallel to the firstmentioned free end branch (17) , and which merges into a third intermediate branch portion (22) which, in its turn, merges into said second free end branch (16) .
6. A cartridge formwork as set forth in claim 5, c h a r a c t e r i z e d i n that said other free end branch (16) intended to be inserted through registering holes (19, 18) in an interconnecting stay (14) and in two neighbouring uprights (lla, lib) each belonging to a formwork cartridge (10a, lOb) of its own, has a noncircular, i.e. oval, elliptical or similar cross section, the round hole (19) of the interconnecting stay (14) being circular.
Description:
A DEVICE FOR FORMWORK CARTRIDGES

This invention relates to devices for formwork cartridges included in a cartridge formwork, wherein each formwork cartridge besides a formwork plate comprises a framework consisting of two parallel uprights connected through intermediate transoms which, in the position of use, extend substantially horizontally, spaced from adjacent transom(ε) , and wherein the outer end faces of the transoms each rests against the side face of the adjacent utright, the connection between said faces resting against each other being secured by means of fixing means in the form of nails and/or fishing plates. Attachment fishing plates are placed along alligned side faces of uprights and transoms, parallel to said formwork plate.

In prior art cartridge formworks of this kind, the ends of the transoms are cut straightly, the end faces forming a right angle with the side faces, the cross-sectional shape of the uprights being rectangular. At each connection point, a number of nails in the order of three-four is used. Upon the filling of concrete, the nails are loaded with respect to cutting-off and extraction, respectively, weakening the framework of the cartridge formwork and which may, especially in tall formwork cartridges, lead to undesired bulges of the formwork plates or to more serious damage.

It is an object of the present invention to reduce these deficiencies, disadvantages and limitations of use to a considerable degree.

This object is substantially realized through designing and shaping the formwork cartridge such that it exhibits the features as defined in the following claim 1.

In a practical embodiment, the front faces of the transoms and of the uprights rest against the back side of the formwork plate, the rear faces of the transoms and of the uprights being free.

The end faces of the transoms and the side faces of the adjacent uprights are disposed under a bevel angle in relation to the longitudinal axis of the transoms, so that the transoms have their largest length along the front face and their shortest length along the rear face.

Because of its inclined end faces and the inclined side faces of the adjacent uprights, a transom can not be displaced rearwardly unless the spacing between the adjacent uprights is increased.

When the formwork cartridge is in use, load against the formwork plate will exactly try to press the transoms rearwardly.

By binding the transoms to the uprights by means of fishing plates adapted to accommodate tensile loads, disposed on the adjacent rear faces on transoms and on uprights, e.g. by means of nail plates of known type, the uprights are maintained efficiently at a mutually constant distance, and this prevents the transoms from being pressed rearwardly in relation to the uprights.

Due to the improvement in strength caused by the present invention, one may reduce the dimensions of uprights as

well as of transoms included in the framework of the formwork cartridge; it normally being sufficient with one nail in addition to the fishing plate at each connection point - three-four nails being used in prior art cartridge formworks having larger dimensions. The increased interconnecting strength at the connection points of the cartridge formwork may in fact be utilized to achieve such a considerable dimension reduction that there remains just space enough for one nail only.

By reducing efficient cross-section of the transoms, at least of the uppermost and lowermost transom, normally forming grips during the handling thereof, in such a manner that the lower respectively upper face, in the position of use, forms an acute angle with a horizontal plane through the straight side face of the respective transom, an improved grip cross-section is achieved, facilitating the handling of the formwork cartridges considerably on the building site.

Known formwork cartridges are general, i.e. they are built symmetrically in respect of a mutual spacing between adjacent transoms. Then, the formwork cartridges can be used also when reversed 180°, causing a certain freedom in handling of the cartridges to be achieved on the site. Consequently, such known formwork cartridges become as strong at the top as at the bottom, referring to a position of use, uprights taking a vertical position, the pressure load from the concrete being significantly larger in the bottom area of the formwork than in the upper layer.

Thus, prior art formwork cartridges become an overdimensioned framework. On the contrary, a formwork cartridge according to the invention should be dimensioned in relation to expected load on the transoms at the various levels thereof, and this leads to the fact that the spacing between adjacent transoms increases successively towards the upper end of the formwork cartridges in the position of use. Such a formwork cartridge can not be used when reversed 180°, but this rather

unessential disadvantage is compensated for through a correctly dimensioned framework, further contributing to reduce the total weight of formwork cartridges.

Thus, in accordance with the invention, considerable weight and volume savings have been achieved, maintaining at least as large a strength (pressure, tensile and bending strength) as known and conventional cartridge formworks having corresponding external measures.

In a cartridge formwork system consisting of a number of formwork cartridges placed in two parallel rows, forming a formwork for a wall, and of lateral interconnecting stays in the form of elongated flat iron strips, an interconnecting means is used according to prior art technique, said means being designed and shaped in order to partly connect the interconnecting stay firmly to one or two uprights in one of said two rows, partly to interconnect two adjacent uprights in the same row. These two interconnecting operations should be effected by means of one and the same interconnecting means which, to this end, is formed as a T-shaped plate haing an elongated slot at one end, and which is assigned a wedge to be driven in subsequently to the T-shaped plate being brought into engagement with interconnecting stays and uprights. Wedges may get wedged and stuck, and it may be difficult to drive them out.

It is a subordinate object of the present invention to provide an interconnecting means which, in a manner known per se, secures interconnecting of interconnecting stays and uprights of two adjacent uprights in the same row.

According to the invention, an interconnecting means of this kind is formed as a kind of double thread hoop which may have a certain self-elasticity, but this is not necessary. The double thread hoop, forming two coherent U-hoops having one common branch, has two free branches forming 90° with each other. One free branch is intended to be passed into

registering round holes in the two adjacent uprights and in the intermediate interconnecting stay, the other free branch being intended to rest against the outside of one upright. The double thread hoop has a first intermediate branch portion parallel to the last-mentioned free branch and intended to rest against the outside of the other upright, and a second intermediate branch portion connecting the first branch portion to the last-mentioned free branch and adapted to rest against alligned side faces of two neighbouring uprights. Finally, the first intermediate branch portion is connected to the adjacent free branch through a third intermediate branch portion which may, but not necessarily must, rest supportingly against the outside of the last-mentioned upright.

In order to prevent that this double thread hoop-shaped interconnecting means becomes stuck in the hole of the interconnecting stay, the first free branch is formed with an oval or elliptic cross-section wherein the large axis is orientated lying in the round hole of the interconnecting stay in the position of interconnection. When the concrete loads the formwork plate, the framework and, thus, the interconnecting stay, the hole-defining side edge portion facing the formwork plate will be pressed vigorously against the first free branch of the interconnecting means; this may complicate, impede or prevent the withdrawal of the branch subsequent to the hardening of the concrete.

When it is desired to withdraw and remove the interconnecting means, the topical free branch is, therefore, turned by means of the interconnecting means, the latter forming an excellent grip, until the small axis of the ellipsis is orientated lying in the interconnecting stay's round hole, the hole-defining side edge portion no longer resting against the oval free branch which, then, may be pulled relatively easily out from the registering holes in the interconnecting stay and in the two neighbouring uprights.

Formwork cartridges according to the invention included in a cartridge formwork system is further explained in the following, reference being made to examples of embodiments illustrated in the accompanying drawings, wherein:

Figure 1 shows a side elevational view of a section of a cartridge formwork comprising three interconnected formwork cartridges;

Figure 2 shows in a top plan view the cartridge formwork section of figure 1, the formwork plates being shown in horizontal cross-section, and wherein both sides of the formwork are visible, but no end structure (the latter may be carried out in a conventional way) ;

Figure 3 shows, on a larger scale, a vertical section through a formwork cartridge's upper part, in the area of an interconnecting means adapted to keep together and secure the positions for partly a flat iron-shaped interconnecting stay, partly two neighbouring uprights at one and the same formwork side;

Figure 4 shows, on a somewhat larger scale than in figure 3, a perspective view of the interconnecting means when connecting together partly the interconnecting stay and two neighbouring uprights, partly two uprights mutually.

Reference is first made to figures l and 2 showing a section of a cartridge formwork, in the embodiment comprising three joined formwork cartridges 10a, 10b and 10c which are identical. Each formwork cartridge 10a, 10b, 10c has a rectangular circumferential shape, symmetrical about a longitudinal central line. On the other hand, the formwork cartridges are unsymmetrical about a lateral central line; this will be further discussed later on.

Each formwork cartridge 10a, 10b and 10c is built up by means of two vertical uprights 11a, lib, lie and a number

(in the embodiment seven) transoms 12a, 12b and 12c, the axial end faces thereof resting against adjacent side faces of neighbouring uprights 11a, lib and lie. The connection points may be secured by means of a nail extending in the lateral direction of the uprights and in the respective transom's longitudinal direction, as well as a fixing fishing plate (nail plate) 13a, 13b, 13c extending parallel to the aligned outer faces of upright and transom. These fishing plates are adapted to accommodate tensile loads caused by a special design/shaping of the land areas on uprights and on transoms, said special shaping being provided in accordance with the present invention.

Said special design consists in a chamferring/bevelling of the land areas on uprights and on transoms at the connection points of the formwork cartridges.

The end faces 12a', 12b' and 12c' of each transom 12a, 12b, 12c and the opposing side face 11a', lib' and lie' of the uprights lla, lib, lie resting thereon, slope under an acute angle with an imaginary plane II - II in figure 2 passing through a common edge on upright and on transom. When the load from the concrete comes, such cooperating inclined faces lla', lib', lie', 12a', 12b', 12c' will place the framework lla-llc,12a-12c in a position to withstand said load better than conventional frameworks having straightly cut ends on transoms and uprights having a rectangular cross-section, displacement forces along the inclined faces giving rise to tensile forces acting in the plane of the fixing fish plates 13a. 13b, 13c. The nail at each connection point is loaded very moderately and will not be subject to harmful cutting-off or pulling- out forces.

In order to adjust the strength of each formwork cartridge 10a, 10b and 10c to expected load, the spacing between neighbouring transoms increases gradually in an upward direction, from below, pressure, tensile and bending

strength being largest in the lower concrete layers where the load is maximum.

Two cartridge formwork side sections, figure 2, are bound together as well as kept at a distance from each other by means of interconnecting stays 14 extending laterally in relation to the course in which the formwork is being erected. These stays 14 are provided with a round hole at each end; otherwise the shaping is conventional, known interconnecting stays having slot-shaped gaps which are brought to cooperate with a T-shaped connector and a wedge.

In accordance with the present invention, in lieu of said T-piece and wedge, a double U-hoop-shaped interconnecting means 15 of thread material is used, likewise serving to connect uprights of two neighbouring formwork cartridges resting against each other and to fix the position of the interconnecting stay end in relation to said uprights resting against each other lla, lib; lib, lie.

This interconnecting means is shown in detail in the perspective view of figure 4, and, likewise, the function thereof appears from figure 3.

The interconnecting means 15 has two free end branches, one first free end branch 16 extending in one direction, preferably forming a right angle with the direction in which the second free end branch 17 extends. The first end branch 16 is intended to be inserted in through registering round holes 18 in two uprights lla, lib of two neighbouring formwork cartridges, said uprights resting against each other, and a hole 19 in the intermediate interconnecting stay 14. The second free end branch 17 is intended to rest supportingly against the other upright side facing away from the upright lib. The second free end branch 17 passes into a first intermediate branch portion 20 extending parallel to the first free end branch 16, and which passes into a second intermediate branch portion 21 which, preferably,

extends parallel to the second free end branch 17. The second intermediate branch portion 21 passes into a third intermediate branch portion 22 passing into the first free end branch 16. The second and third intermediate branch portions 21, 22 lie substantially in the same plane, and are intended to rest supportingly against that side face of the upright lib facing away from the adjacent upright lla.

Such an interconnecting means 15 is formed to function alone and is easy to handle. It may be formed such that the first intermediate branch portion 20 becomes lying at an appropriate distance from the upright faces in the position of use, figure 4, so that fingers may be inserted in the gap between branch portion 20 and upright faces, especially when the cartridge formwork is to be dismounted.

Load from the concrete may result in that the hole edge portion defining the hole 19 in the interconnecting stay and facing toward the interior of the formwork is pressed with such a large force against the interconnecting means 15 that the cartridge formwork opposes being demolished.

To this end, the first free end branch 16 of the interconnecting means 15 may be formed with an oval/ elliptic cross-section such as shown in figure 3, the cross-sectional ovality being orientated such that the large axis of the ellipsis is lying in the position of use of the interconnecting means, figures 3 and 4. When turning the first free end branch of the interconnecting means 15 by means of the first intermediate branch portion 20 pivoting 90° upwardly, the small axis of the ellipsis is brought to become lying in the round hole 19 of the interconnecting stay 14. Then, the pressing force from said hole edge portion is neutralized or reduced, whereafter the interconnecting means 15 may be removed easily.

As previously indicated, the designs and shapings according to the invention give rise to volume and weight savings,

maintaining the same strength as a known/conventional cartridge formwork system having the same external measures.

This volume/weight reduction may as far as the transoms are concerned advantageously be utilized such that at least some transoms are formed with a trapeziodal cross-section such as the upper transom 12a in figure 3. Such a shaping gives a far more convenient grip than known transoms having a rectangular cross-section.

Besides the framework lla,12a, lib,12b, lie,12c, each cartridge formwork 10a, 10b and 10c comprises a well known formwork plate 23a, 23b and 23c, respectively.