DEVICE FOR JOINTS IN CONCRETE FLOORS

Abstract: A device for joints in concrete floors is disclosed, comprising edge linings (1) and one or more clasps (2). The clasps (2) and the edge linings (1) are interconnected in a fixed manner, and each clasp (2) is designed as two laterally projecting arches (3) which join in a downwardly extending, arcuate projection (4). Moreover, a method for casting concrete floors is disclosed, comprising the steps of casting the concrete floor on the base and steel trowelling of the concrete surface. The device is pressed down in the concrete before hardening thereof, whereupon the edge linings (1) are adjusted in the steel trowelling of the concrete surface. The concrete floor is sawn between the edge linings (1) to a depth which is smaller than the depth of the clasps (2), whereupon the now formed joints are filled with a semi-elastic compound. Furthermore, means for pressing down or mounting of the device, and a casting method in which the device is mounted in situ before casting are disclosed.

Description: DEVICE FOR JOINTS IN CONCRETE FLOORS The present invention relates to a device for joints in concrete floors, and a casting method in which the device is used. In the process of making a large-surface concrete floor, there is always a risk of shrinkage cracks. By joint spacing of the concrete slab attempts have been made to avoid such cracks. When making concrete floors, both traditionally reinforced floors and fibre-rein¬ forced concrete floors, these joints have lately been sawn after casting and hardening of the concrete, fol¬ lowed by filling the joints with a semi-elastic sealing compound. However, the joints are not protected against mechanical damage and are easily damaged by e.g. truck traffic. Edge linings have been made in expansion joints, said linings being mounted in the bulkheads of the joints, but this is too expensive and takes too much time to be used on a large scale. A further problem arising in joint spacing is that the concrete slabs rise and are pressed down differently when mechanically damaged, thereby causing differences in level between the concrete slabs. In order to try to prevent such differences, dowels are normally used which are cast into one slab part and which in the other slab part are coated with bitumen to allow sliding. One object of the present invention is to provide a device for joints in concrete floors, by means of which the problems with shrinkage cracks, damaged joint edges and differences in level between the concrete slabs are avoided. A further object of the present invention is to provide means for mounting the device according to the present invention in the concrete floor. One more object of the present invention is to pro¬ vide a method for casting concrete floors, in which the device according to the invention is used. These problems with shrinkage cracks, damaged joint edges and differences in level between the slabs are solved by means of the device, the means and the method as claimed in claims 1-6. Briefly, the present invention thus relates to a device for joints in concrete floors, which comprises edge linings with clasps. According to the present invention, the clasps and the edge linings are intercon¬ nected in a fixed manner, and each clasp is designed as two laterally projecting arches which join in an arcuate, downwardly extending projection. The present invention also relates to a means for pressing down the device for joints in concrete floors, and a means for mounting the device for joints in con¬ crete floors before casting the concrete floor. Moreover, the present invention relates to a method for casting concrete floors, comprising the steps of casting the concrete floor on the base and steel trowel¬ ling of the floor surface. According to the present invention, the device according to claim 1 is pressed down in the concrete before hardening thereof, whereupon the edge linings are adjusted in the steel trowelling of the concrete surface. The concrete floor is sawn between the edge linings to a depth which is smaller than the depth of the clasps, whereupon the now formed joints are filled with a semi-elastic sealing compound. The present invention also relates to a method in which the device for joints in concrete floors is mounted on means in the form of trestles, whereupon the concrete floor is cast and steel trowelled. The concrete floor is sawn between the edge linings to a depth which is smaller than the depth of the clasps, whereupon the now formed joints are filled with a semi-elastic sealing compound. Preferred embodiments of the device and the means according to the present invention will be described below with reference to the accompanying drawings. These embodiments must not be considered restrictive for the scope of the present invention. Fig. 1 is a top plan view of a preferred embodiment of the device for joints in concrete floors according to the present invention. Fig. 2 is a cross-sectional view of a preferred embodiment of the device for joints in concrete floors according to the present invention in a reinforced con¬ crete floor. Fig. 3 is a top plan view of a preferred embodiment of a means for pressing down the device for joints in concrete floors. Fig. 4 is a side view of the means for pressing down the device for joints in the concrete floor. Fig. 5 is a top plan view of a preferred embodiment of a means for mounting the device for joints before casting the concrete. Fig. 6 is a side view of the means for mounting the device for joints before casting the concrete floor. The embodiment of the device for joints in concrete floors according to the present invention as illustrated in Figs 1 and 2 comprises edge linings 1 and one or more clasps 2, the clasps 2 being attached to the edge lin¬ ings 1. Thus, the edge linings 1 are fixed relative to each other. The clasps 2 are designed as two laterally projecting, V-shaped arches 3 which join in a downwardly extending, U-shaped projection 4. The inventive device is used when casting concrete floors, in which process the device is pressed down in the concrete before hardening. The concrete floor is steel trowelled and then also the edge linings 1 are adjusted. After a few days, a joint 5 is cut in the con¬ crete floor between the edge linings 1. The joint 5 is made so deep that it extends into the U-shaped projec¬ tion 4 and through the reinforcement 6 of the concrete floor, but not so deep that the clasps 2 are sawn apart. This joint 5 is then filled with an elastic compound. Since the clasps 2 are bent as shown in Fig. 2, the shrinkage of the area divided by the joints 5 can take place without the clasps 2 being damaged or preventing shrinkage. Cracks do not arise during shrinkage since the slab parts on each side of the sawn-up joint are allowed to shrink without resistance from the other ele¬ ments included in the concrete. No difference in level is possible between the edge linings 1, since the edge linings 1 are kept in a fixed position relative to each other by means of the projections 4 of the clasps 2. The embodiment shown in Figs 3 and 4 of a means for pressing down the device in Figs 1 and 2 in the concrete floor comprises a spear 7 with at least one spear head 8 and fastening means 9 having a clamping function 10 for fixing the device in Figs 1 and 2. The pressing-down means is also fitted with a handle 11 at the top of the spear 7. The pressing-down means is used when the device in Figs 1 and 2 should be pressed down in the cast con¬ crete. Such pressing-down means permit vertical and horizontal adjusting of the edge linings and fixing thereof in the correct position. The embodiment shown in Figs 5 and 6 of a means for mounting the device in Figs 1 and 2 before casting of the concrete floor comprises a cup-shaped recess 12 for the arcuate projections 4 of the clasps 2, a recess 13 for receiving the edge linings 1 and a recess 14 for the laterally projecting arches 3 of the clasps 2, and a base portion 15. The mounting means is used when the device in Figs 1 and 2 is mounted in situ before casting of the con¬ crete floor. The mounting means can also be fixed to the base by "local" concrete blocks which are cast round the base portion 15 of the mounting means.

Claims: CLAIMS 1. Device for joints in concrete floors which are made as industrial products, said device comprising edge linings (1) and one or more clasps (2), c h a r a c ¬ t e r i s e d in that said edge linings (1) and said clasps (2) are interconnected in a fixed manner, and that each clasp (2) is designed as two laterally pro¬ jecting arches (3) which join in an arcuate, downwardly extending projection (4) . 2. Means for pressing down the device according to claim 1 in the concrete, c h a r a c t e r i s e d in that said means comprises a spear (7) having at least one spear head (8) and mounting means (9) having a clamping function (10) for fixing the device according to claim 1. 3. Means for mounting the device according to claim 1 before casting of the concrete floor, c h a r a c ¬ t e r i s e d in that said means comprises a cup-shaped recess (12) for the arcuate projection (4) of said clasps (2), a recess (13) for receiving the edge linings (1) and a recess (14) for the laterally projecting arches (3) of said clasps (2), and a base portion (15) . 4. Method for casting concrete floors which are made as industrial products, said method comprising the steps of casting the concrete floor on the base and steel trowelling of the concrete surface, c h a r a c ¬ t e r i s e d in that the device according to claim 1 is pressed down in the concrete before hardening there- of, the edge linings (1) are adjusted in the steel trowelling operation, and the concrete floor is sawn between the edge linings (1) so deep that the cut reaches down in the arcuate projection (4), but not so deep that the clasps (2) are sawn apart, whereupon the sawn-up joints are filled with a semi-elastic compound. 5. Method for casting concrete floors according to claim 4, c h a r a c t e r i s e d in that the device according to claim 1 is pressed down in the concrete by means of at least one means according to claim 2. 6. Method for casting concrete floors which are made as industrial products, said method comprising the steps of casting the concrete floor on the base and steel trowelling thereof, c h a r a c t e r i s e d in that the device according to claim 1 is mounted on the means according to claim 3 before said casting of the concrete floor and steel trowelling thereof, the con¬ crete floor is sawn between the edge linings (1) so deep that the cut reaches down in the arcuate projection (4), but not so deep that said clasps are sawn apart, where- upon the sawn-up joints are filled with a semi-elastic compound.

Inventors: JOENSSON SVEN-GUNNAR, JOENSSON, SVEN-GUNNAR
Applicants: JOENSSON SVEN GUNNAR, JOENSSON, SVEN-GUNNAR
Application year: 1993
Main classification: E04F15
IPC codes: E01C11, E04F15