Trowelling apparatus for cement surfacing machines

Claim 1

A BLADE ASSEMBLY FOR ATTACHMENT TO A ROTATABLE SWEEP ARM OF A MACHINE FOR TROWELLING THE SURFACE OF CEMENT AND COMPRISING A HORIZONTAL PLATE OF TRUNCATED TRIANGULAR FORM, A BAR-LIKE MEMBER UNDERLYING THE CENTRAL PORTION OF THE BOTTOM SURFACE OF THE PLATE AND WHEREBY THE APEX PORTION OF THE PLATE PROTRUDES FROM ONE SIDE OF THE BAR-LIKE MEMBER AND THE BASE PORTION OF THE PLATE PROTRUDES FROM THE OTHER SIDE OF THE BAR-LIKE MEMBER, THE BAR-LIKE MEMBER BEING SECURED TO AND PROJECTING FROM THE END OF THE SWEEP ARM, A CEMENT TROWELLING BLADE ADAPTED TO BE POSITIONED UNDERNEATH THE BAR-LIKE MEMBER AND TO BE DETACHABLY CARRIED BY THE TRIANGULAR PLATE, A PAIR OF INWARDLY FACING CHANNEL MEMBERS FOR RECEPTION OF THE PLATE AND CARRIED UPON THE SIDE PORTIONS OF THE UPPER FACE OF THE BLADE AND HAVING THEIR INNER VERTICAL FACES SPACED APART A DISTANCE SOMEWHAT GREATER THAN THE DISTANCE BETWEEN THE BASE OF THE PLATE AND ITS TRUNCATED APEX, EACH CHANNEL HAVING AN UPPER INTURNED HORIZONTAL FLANGE, ONE FLANGE OVERLYING THE BASE PORTION OF THE PLATE AND THE OTHER FLANGE OVERLYING THE APEX PORTION OF THE PLATE WHEN THE PLATE IS RECEIVED WITHIN THE CHANNELS, ONE END PORTION OF EACH FLANGE BEING FORMED WITH A SLOT OF JUST SUFFICIENT SIZE TO PERMIT PASSAGE OF THE APEX PORTION OF THE PLATE INTO AND OUT OF THE SLOT, AND STOP MEANS PROJECTING INTO EACH CHANNEL AND AGAINST WHICH THE PLATE IS URGED BY CENTRIFUGAL FORCE AS THE SWEEP ARM ROTATES, EACH SAID STOP MEANS RETAINING THE BLADE ON THE TRIANGULAR PLATE AND LOCATING THE TRIANGULAR PLATE IN THE CHANNELS WITH THE RESPECTIVE FLANGE SLOT OUT OF REGISTER WITH THE SAID APEX PORTION OF THE PLATE.