1. A SAFETY DEVICE FOR A TRACTOR HAVING A PEDAL ACTUATED CLUTCH AND AN IMPLEMENT CARRYING FRAME MOUNTED THEREON FOR VERTICAL SWINGING MOVEMENT BY UPPER AND LOWER LINK MEMBERS, COMPRISING: A LINK SERVING AS SAID UPPER LINK MEMBER, THE EFFECTIVE LENGTH OF WHICH IS SHORTENED UPON APPLICATION OF A PREDETERMINED COMPRESSIVE FORCE TO PERMIT SAID FRAME TO SWING UPWARDLY WITH RESPECT TO SAID TRACTOR; A LEVER PIVOTALLY MOUNTED INTERMEDIATE ITS ENDS ON SAID FRAME, SAID LEVER HAVING LIMITED LATERAL MOVEMENT ALONG ITS PIVOTAL AXIS; A STOP MEMBER HAVING A SLOT FORMED THEREIN SECURED TO SAID FRAME SO THAT, IN ONE POSITION, SAID LEVER IS RECEIVED IN SAID SLOT AT A POINT ABOVE THE PIVOTAL AXIS OF SAID LEVER AND HELD AGAINST PIVOTAL MOVEMENT IN ONE DIRECTION AND, IN ANOTHER POSITION, SAID LEVER WILL CLEAR SAID STOP MEANS; GUIDE MEANS SECURED TO SAID TRACTOR BELOW SAID CLUTCH PEDAL; AND AN ELONGATED FLEXIBLE MEANS TRAINED OVER SAID GUIDE MEANS AND SECURED TO SAID CLUTCH PEDAL AND TO SAID LEVER AT A POINT BELOW ITS PIVOTAL AXIS, THE ARRANGEMENT BEING SUCH THAT WHEN SAID LEVER IS RECEIVED IN SAID SLOT, UPWARD MOVEMENT OF SAID FRAME RELATIVE TO SAID TRACTOR CAUSES CLUTCH DISENGAGING MOVEMENT OF SAID CLUTCH PEDAL, SAID CLUTCH BEING REENGAGEABLE WHILE SAID FRAME IS IN AN ELEVATED POSITION BY DISLODGMENT OF SAID LEVER FROM SAID SLOT AND MOVEMENT OF SAID LEVER LATERALLY TO A STOP-CLEARING POSITION.