Press

TOX-Round Joint sheet metal joinings as technical/economical alternative to conventional welding and/or spot welding of storage construction elements.

Nowadays the subject intralogistics, i.e. the storage-, commissioning-, conveying- and material handling engineering in production and distribution companies is on all tongues. Ordered today, delivered tomorrow, that’s what the final customer requires who sends his orders via internet and expects the delivery on the following day. Specially for distributors this means to keep a variety of products in sufficient quantities in stock. This is the reason why the business of the manufacturers of high-bay storages has enormously increased during the past years. But also competition has increased: this is due to the fact that economic recession has left deep skid marks in innovative logistics, too, so that the manufacturers are forced to take optimization measures. This refers to production processes as well as to organizing measures as it is shown by an example given by the German Dexion GmbH, located in Laubach/Hessen, an affiliate of the Norwegian Constructor Group. Since quite a long time, Dexion/Constructor has approached alternative plate working technologies and specially joining technologies in order to reduce production cost and above all the cost of (thermal) joining by welding in order to improve its competitive strength in a market which is more hotly contested than ever before. The design engineers of Dexion/Constructor stroke out untrodden paths by putting all relevant joining and connecting technologies on a test bench. Their examination included aspects like technical suitability, technical availability, capital and installation expenditure, process integration, operating and maintenance cost, energy efficiency and the like. Within this scope, they also tested alternative mechanic joining and connecting techniques and ran into the TOX-Round Joint connecting technique of the medium-sized company TOX PRESSOTECHNIK GmbH & Co. KG, located in the Southern part of Germany, in D-88250 Weingarten.

TOX-Round Joint connections as technical-economical alternative

The TOX-Round Joint technology means a cold-forming process in which an aesthetically appealing, easy producible and by definition non – detachable button – like joining of several metal sheets of equal or different thickness and materials is produced. Expressed in simplified terms, this is effected exclusively by the TOX-tool consisting of punch and die, pressed together by a press system using an hydraulic or pneumohydraulic drive, e.g. the TOX-Powerpackage, or a high tech electric servo drive like TOX-ElectricDrive, thereby joining the metal sheets with one stroke. The advantages, compared to thermal and other mechanic joining and connecting procedures, are captivating. Compared to welding lines and spot welding plants, the cost of this press joining do by far not reach their high investment costs for plants and installation; and the maintenance and repair cost are just a fractional part. And also the energy consumption is considerably lower and no water cooling systems are required. The net operating costs are reduced to the comparably minimal consumption of electricity and compressed air. Spare parts like electrodes or weld tips are not needed at all. But, as already mentioned above, the TOX-Round Joint connects two or more metal sheets of different thicknesses even if they are galvanized or coated. And also intermediate layers such as foils, glue or insulating material are possible. Due to the fact, that the joining takes place by cold forming without cutting and interconnection of the material as used with conventional clinching, no corroding cut edges are created. And last not least it is possible to set the TOX-Round Joints either with handheld tongs or with robot tongs, with simple devices, with stand-alone presses or inline press stations. It is possible to set single points each time or multiple points simultaneously using the TOX-Multipoint tools. All these advantages finally convinced the responsible persons from Dexion so that they completely equipped a new product line for the series production of girders for high-bay storages with the TOX joining technique.

Completely galvanized and of utmost carrying capacity – shelf girders without weld joints

As the shelf girders are intended to bear the high weight of paletts and other charge carriers, they are an important structural member of a high-bay storage system. The new joining technique has therefore been subject to comprehensive tests, and the quality of the joinings has been documented in so-called TOX test reports. In the case of the shelf girders, the technology of the TOX-Round Joint is twice applied, namely for the production of the girder profile and for the fastening of the brackets for hanging in the shelf supports. The joining of the girder profile of sheet metal, produced by a section roll process from a coil, is done in a „flying“ way, i.e. in a press station through which the prefabricated and section rolled girder profiles are transported. When passing through, four TOX-Round Joints each are simultaneously placed at a distance of 100 mm. Depending on the series of the shelf technique and permissible load, the shelf girders are made of metal sheets having a thickness of 1.4 to 2.2 mm, so that in folded condition, 2 layers of sheets are joined. The raw metal sheet is already galvanized and needs no further coating or treatment by the manufacturer after joining. Due to the inline integration of the TOX station, the girder production could be largely automated, too. The production plant equipped with several TOX stations manufactures each week up to 20 000 shelf girders of different types. Two clevis type connectors must be mounted to each shelf girder and this is also done by the TOX-Round Joints. Here a so-called three-sheet connection is applied consisting of the section rolled girder profile with two layers of, for example, galvanized metal sheets 1.4 to 2.2 mm thick, and the clevis type connector of galvanized sheet metal 4 mm thick. For these three-sheet connections two complete plants have been designed and delivered for mounting up to 40 000 clevis type connectors to the shelf girders a week.

Conclusion

The functioning of the joining technology TOX-Round Joint is perfect and most reliable so that Dexion promotes the sale of its new product line „P 90 Silverline girders“ with the following catchwords: „No weld seams, innovative TOX-Joining, completely galvanized, interesting price/performance ratio”. There remains nothing to add, or perhaps the fact that the TOX-tools distinguish themselves by a very high solidity and that the quality of the TOX joinings between girder profile and the clevis type connector is continuously and nondestructively registered and documented by the TOX-Monitoring system.