in referring to the drawings , it can be seen that in its simplest form , each castrating head comprises a case 1 , presenting on its front side 2 an opening 3 , and enclosing a severing device in the form of a blade 4 mounted on a shaft 5 whose axis extends to the plane of the row to be treated approximately perpendicular to the stems of the corn seedlings m . blade 4 is bent in a right angle at its ends to form two knives 6 . its axis extends onto the plane of the row to be treated approximately perpendicular to the stems of corn . the vertical edges of opening 3 each present a shutter in two parts 7a and 7b , each of which is substantially planar . part 7b is fastened onto 7a which can pivot on an approximately vertical axis 26 and can be immobilized at the required angle by mechanism 27 as shown in fig1 and 2 . shutter 7b which is approximately shaped like a triangle is arranged so that one of its sides is approximately vertical and is journalled about a substantially vertical axis at element 28 toward the lower end of this side on shutter 7a . in this manner , the two other sides 8 and 9 form two adjustable upper and lower ramps respectively . the function of ramps 8 is to straighten panicle p to be cut as well as the leaf in which it is located in order to facilitate their introduction into case 1 . on the other hand , the function of ramps 9 is to bend down the underlying leaves so that they will not enter the case . it is thus possible to cut off the panicles comprising the male elements without altering in an undesirable manner the greenery of the corn seedling . according to an embodiment particularly applicable to machines carried by a tractor equipped with a slope correction system , the heads are affixed on bars 10 joined by journalled links 11 between them . each one of bars 10 is supported by the end of a pair of arms 12 journalled by its other end on an upright 13 affixed to the tractor vehicle ( not shown ) and which is able to pivot on an approximately vertical plane because of the action of jack 14 . each one of bars 10 can pivot by the interposition of a shaft 15 on a plane perpendicular to that formed by arm 12 and corresponding upright 13 . therefore , as shown in fig5 if the rows of corn to be treated are located on a slope , it is possible , by careful adjustment of the angle of arms 12 , to keep all castrating heads approximately equidistant from the ground . as shown in fig4 and 7 , a movable parallelogram linkage connecting assembly is formed by a pair of arms 12 , a respective upright 13 , and a relatively short arm 12a which is movable , while remaining substantially perpendicular to the ground . the rotary driving of blades 4 is achieved by the interposition of a hydraulic motor 16 mounted at the end of one of shafts 5 . the movement is transmitted to the other blades by belts , such as 17 ( fig4 ). each one of cases 1 is linked to guides 18 each supported by a shank 19 that can slide and be immobilized in a catch of holder 20 affixed to the case . the function of these guides is to straighten the seedling , which would have pushed obliquely in its row on a transversal plane . this makes it possible to guarantee that it will be possible to introduce its panicle into slot 3 of the corresponding head . although the supporting rods 10 can be bent horizontally , it is essential that slots 3 of the heads remain vertical . for this purpose , a further linkage assembly is provided . each one of cases 1 can freely pivot around the axis of shaft 5 by the driving of the blade by the interposition of link 21 , journalled at one of its ends onto the end of a clamp 22 of case 1 , and at the other onto axis 23 parallel to shaft 5 and affixed to mobile side 12a of the deformable parallelogram comprising corresponding arms 12 . fig8 is an example of a way to link case 1 to bar 10 . thus , shaft 5 extends through bearing 24 externally comprising a shoulder on which the rear side of case 1 is engaged , which is held by plate 25 . the present invention is , of course , not limited to the embodiment described and shown , but rather extends to all varying shapes and sizes .
corn sterilizing machine of the type using rotary blades . the machine uses a castrating head in the form of a case enclosing a rotary blade . the front surface of the case has a slot allowing for the introduction of the panicle to be cut . each one of the vertical edges of the slot has a pivotable shutter having two upper and lower ramps , respectively .