Characteristics of the machine

The machine is equipped with one or several work units which can be moved up and down on double rotary slides with linear ball bearings. Via an additional height adjusting column, the units are adjusted by means of a hand-wheel to the required component thickness. For exact adjustment, the hand-wheel has an adjustable ring with scale.

The grinding units are constructed on a two-pulley-system with the driven contact wheel and tensioning idler pulley. This pulley is additionally used for belt tracking by means of a hand-wheel arranged outside the belt guard. Belt tensioning is by a pneumatic cylinder taking effect on the idler pulley and by means of a compressed air regulator it is easily adjustable. For belt changing, belt tensioning is released by a hand-lever valve.

In order to keep very small parts on the conveyer belts, for non-magnetic metals special hold-down rollers can be installed which firmly press the components onto the belts. In case of magnetic components, a magnetic plate is fitted in the grinding table below the conveyer belt. To eliminate the magnetism remaining on the components, a demagnetiser is arranged behind the last grinding station.

The machine type GB 212 has definite advantages compared with usual flat grinding machines:

1. The grinding pressure of the belt heads can be exactly determined because the belt head and belt guard with hold- down rollers are mounted on different slides. The belt head is balanced with an adjustable balance weight. The contact pressure of the hold-down rollers can therefore be determined independently from the grinding pressure.

This patent system has the consequence that only the contact wheel and the belt tensioning arm follow the component contour at constant grinding pressure, whereas the belt protection guard with the hold-down rollers remains at the adjusted height. This sensitive control results in an excellent surface quality, long life of the belt and largely avoids the concurrence of chatter marks and chamfering of edges as well as component slip which can arise when using the usual flat grinding machines.

2. The work spindle has double bearings and compared with the single bearing shaft of a normal motor it offers the guarantee that the overall component width is correctly ground without heavy grinding on one side.