Screening machine

Claim 1

A MATERIAL SCREENING MACHINE, WHICH COMPRISES A SCREEN FRAME, A FINE MESH SCREEN DISPOSED ACROSS SAID FRAME, A COARSE MESH SCREEN DISPOSED ACROSS SAID FRAME IN UNDERLYING PARALLEL SPACED RELATION TO SAID FINE MESH SCREEN, A TENSION ADJUSTMENT MEANS CONNECTED TO SAID FRAME AND TO SAID FINE MESH SCREEN TO SELECTIVELY ADJUST THE TENSION THEREOF IN EACH OF TWO DISTINCT LATERAL DIRECTIONS, A TENSION ADJUSTMENT MEANS CONNECTED TO SAID FRAME AND TO SAID COARSE MESH SCREEN TO SELECTIVELY ADJUST THE TENSION THEREOF IN EACH OF TWO DISTINCT LATERAL DIRECTIONS, SAID FINE AND COARSE MESH SCREENS BEING DISPOSED FOR INDEPENDENT TENSIONING ADJUSTMENT BY THEIR RESPECTIVELY ASSOCIATED TENSION ADJUSTMENT MEANS, A FIRST PLURALITY OF PLATE MEMBERS SECURED TO SAID FINE MESH SCREEN AT INDIVIDUALLY DISTINCT LATERALLY SPACED APART LOCATIONS THEREON, A SECOND PLURALITY OF PLATE MEMBERS SECURED TO SAID COARSE MESH SCREEN AT LOCATIONS THEREON UNDERLYING CORRESPONDING PLATES OF SAID FIRST PLURALITY THEREOF, EACH OF SAID FIRST PLURALITY OF PLATES BEING DISPOSED TO RECEIVE IMPACT FORCES AND TO TRANSMIT SUCH RECEIVED IMPACT FORCES TO CORRESPONDING UNDERLYING PLATES OF SAID SECOND PLURALITY THEREOF, AND A PLURALITY OF TAPPETS EACH DISPOSED FOR RECIPROCATING MOVEMENT ALONG A PATH INTERSECTING WITH A CORRESPONDING PLATE OF SAID FIRST PLURALITY THEREOF AND GENERALLY NORMAL TO THE PLANES OF SAID FINE AND COARSE MESH SCREENS TO STRIKE SAID PLATE AND THEREBY EXCITE VIBRATIONS IN SAID FINE AND COARSE MESH SCREENS NORMAL TO THEIR RESPECTIVE PLANES TO AID IN THE SCREENING OF MATERIAL THROUGH SAID SCREENS.