Semaphore arm vehicle signal

Claim 1

IN COMBINATION, A VERTICALLY DISPOSED WALL HAVING INNER AND OUTER SURFACES, A CYLINDER HAVNG AN ELONGATED CHAMBER, A MOVABLE PISTON DISPOSED IN SAID CHAMBER AND DIVIDING SAID CHAMBER INTO TWO COMPARTMENTS, A ROD CARRIED BY SAID PISTON, A SIGNAL MEANS INCLUDING A HORIZONTALLY SWINGABLE ARM PIVOTALLY ATTACHED AT ONE END TO THE OUTER SURFACE OF SAID WALL, AN ARCUATE PUSH BAR HAVING AN ARCUATE EXTENT OF THE ORDER OF NINETY DEGREES RIGIDLY FIXED AT ONE END TO SAID ARM ADJACENT THE PIVOTALLY ATTACHED END OF THE LATTER AND EXTENDING SUBSTANTIALLY HORIZONTALLY THROUGH AN APERTURE IN SAID WALL, SAID PUSH BAR BEING PIVOTALLY CONNECTED AT ITS OTHER END TO THE FREE END OF SAID ROD, SAID SIGNAL MEANS BEING MOVABLE BETWEEN TWO OPERATING POSITIONS, A VACUUM SOURCE, AND MEANS FOR SELECTIVELY INTERCONNECTING SAID SOURCE WITH ONE OF SAID COMPARTMENTS TO CAUSE SAID PISTON TO MOVE SAID ROD TO ITS EXTENDED POSITION WHILE SIMULTANEOUSLY INTERCONNECTING THE