Concrete Block Machines

Parameters to Describe the Dynamic Characteristics of
Production Boards

Fig. 1 Vibratory subassembly of a concrete block machine
(schematic view)

Fig. 2 Test setup and variables for parameter measurement according to Approach 1.

Fig. 3 Schematic view of the test setup according to Approach 2.

Fig. 4 View of the “test tongs” pilot-scale measuring device.

Fig. 5 Primary data gathered by the “test tongs” device: load-time curve (blue), deformation-time curve (red).

Fig. 6 Load-deformation curve for various production board materials.

Fig. 7 Determination of the correlation between the measured rigidity of the production board and the anticipated compaction effect (bulk density) for identical machine settings.

Fig. 8 View of the “drop hammer” pilot-scale measuring device.

Fig. 9 Development of acceleration over time (measured example) .

Fig. 10 Impact rigidities S_K of tested production boards.

Fig. 11 Development of impact rigidity S_K over the service life (softwood boards).

Fig. 12 Correlation between the impact rigidity S_K of the production board and the anticipated compaction effect (bulk density).

Fig. 13 Block diagram of the measuring system.

Fig. 14 CAD model of the sensor head.

Fig. 15 View of the measuring system positioned on a block mold.

Fig. 16 Measuring system in the concrete block machine.

Fig. 17 Measuring system in the concrete block machine.

Fig. 18 Parameter development (assuming a qualitative time line).

 So-called board machines are used for the manufacture of the major share of concrete products in Germany and Europe. These are concrete block machines that mold and compact the items directly on production boards (or base plates) (Fig. 1). These boards are also used for the transport and storage of the products in high-bay racks until the layers are stacked upon each other.

A very intense shock vibration process is normally used for the molding and compaction of the concrete mix. This method uses coordinated movements of individual subassemblies of the production system (working masses) to generate periodic impact sequences in defined intensities that are transferred into the concrete mix to be compacted via the molding subassembly. The production boards are part of the working masses of the block machine’s vibratory subassembly, which is a complex oscillation system whose design is of key importance with regard to the achievable quality of the concrete products....