METHOD AND DEVICE FOR CHECKING THE WORKING CONDITIONS DURING GRINDING IN CENTRELESS GRINDERS

摘要

1461307 Centreless grinding M POSSATI [trading as FINIKE ITALIANA MARPOSS SAS] 29 Jan 1974 [9 Feb 1973] 4198/74 Heading B3D A method for checking the working conditions during machining in a centreless grinder, the workpiece 10, Fig. 1, being supported by support means 13, comprises generating a first measurement signal responsive to the position of the workpiece outer surface at a point close to the support means surface, generating a second measurement signal responsive to the workpiece outer surface at a point located diametrically opposite to the proceding point, processing the first and second measurement signals to obtain a third signal responsive to workpiece diameters, and comparing the first measurement signal with a reference signal to obtain a signal for monitoring the position of the support means surface. The grinder may be of the plunge machining type having a working wheel 11 and a feed wheel 12 between which is a knife 13 in a support 14. An electronic comparator 16 is mounted on a slide (21, Fig. 2, not shown) and has moving arms 17, 18 provided with feelers 19, 20 for gauging the size of the workpieces, the feeler 20 being adjacent the knife 13. Each feeler is associated with an inductive transducer, the output signals of which are fed to a summing unit to produce a signal indicative of the size of the workpiece and to control the machining operation. The signal from feeler 20 is also compared with a reference voltage and when higher than that voltage operates an alarm and a control unit which actuate a motor to raise the knife relative to its support and thus compensate for wear of the knife. The circuit may be operated so as to give a direct indication of the wear of the knife. The method may be applied to a grinder of the through-feed type having a working wheel 51, Fig. 4, and a feeding wheel 52 consisting of two parts 55, 56. The workpiece 50 is supported on a knife 53 between the wheels, and a head 57 of a comparator has a feeler disposed between the parts to measure the wear on the knife and a second feeler (not shown) on the other side of the workpiece. The method may also be applied to machines in which the workpiece is supported on a pair of shoes and rotated by a magnetic spindle.