Arrangement testing hardness of small workpieces - has microphone picking up frequency distribution as workpiece lands on support and supplying comparator controlling deflector

摘要

The hardness of continuously and sequentially delivered workpieces, esp. small ones, is tested. They are allowed to fall upon a non-oscillating support. The frequency distribution of the sound produced as the workpieces hit the support is compared with a stipulated frequency distribution corresp. to a desired degree of hardness. A distributor (2) feeds the workpieces sequentially to the support (12). A microphone (28) is installed near the latter (12) and is connected to a frequency-distribution comparator (32). A deflector (18) is controlled by the latter (32) to reject those workpieces whose frequency distribution lies outside the predetermined limits of tolerance. The distributor can be in the form of a vibrator enclosed in a sound-insulated housing (10).