with reference to the figures , the reference numeral 1 generally designates a carousel - type distribution unit for handling and planting vegetable species according to the invention . the distribution unit 1 is of the type that can be mounted on a frame 2 of an agricultural machine and is composed of a carousel 3 , along the circumference of which there are twelve conical cups 4 , each of which is composed of two half - cones 4 a and 4 b mutually articulated about two respective pivots 5 which have a substantially horizontal axis . the cups 4 are adapted to contain the plant species and to open and drop the plants contained therein into two underlying conveyance channels 6 . the conveyance channels 6 are arranged symmetrically with respect to the vertical axis of rotation of the carousel 3 in a peseudodiametrical position . the channels 6 have an upper inlet 6 a shaped like a truncated pyramid and extending with a lower tube - shaped portion 6 b which has a square cross - section and leads into a chamber 7 defined inside a respective hollow plowshare 8 which forms a furrow in the soil . the plowshare 8 is provided by two mutually connected side walls 9 and contains a plant ejector foot 10 . [ 0022 ] fig1 and 2 illustrate the kinematic chain of the mechanical elements that transmit the rotary motion to the carousel 3 . the carousel 3 is driven by a vertical shaft 11 internally coaxial to a sleeve 12 , which is rigidly coupled to the frame 2 and is designed to support the carousel 3 . the vertical shaft 11 is rotatably supported within the sleeve 12 , with the interposition of two bearings 14 , and is rigidly coupled to the carousel 3 by means of a contoured nut 15 screwed onto the upper end of the shaft 11 . a first bevel gear 16 is instead arranged at the lower end of the shaft 11 and meshes with a second bevel gear 17 which is keyed to a shaft 18 arranged substantially horizontally . the shaft 18 is rotatably supported by two bearings 19 accommodated in seats which are fixed on the frame 2 . the bevel gear 17 is keyed in a central position on the shaft 18 and a cylindrical gear 20 and a first pinion 21 are keyed to the shaft 18 respectively at its opposite ends which lie on the outside of the bearings 19 . the pinion 21 meshes with a transmission chain 22 , in turn driven by a second pinion 23 which is actuated by a driving bar 24 coaxial thereto . as shown more clearly in fig6 a torque limiter , generally designated by the reference numeral 25 , is interposed between the second pinion 23 and the driving bar 24 . the torque limiter 25 is composed of a sleeve 26 , which rotates rigidly with the bar 24 and can slide axially thereon , and is provided with a series of six contoured protrusions 27 which engage respective seats 28 formed in the front side 29 of the second pinion 23 . the sleeve 26 is kept in contact with the second pinion 23 by a cylindrical spring 30 acting between an adjustment ring 31 , which is screwed onto the bar 24 , and the end of the sleeve 26 . in this manner , by adjusting the compression of the spring 30 against the sleeve 26 by means of the ring 31 , it is possible to preset the torque to be transmitted by the driving bar 24 to the second pinion 23 . as to the torque limiter 25 , it should be noted that among the protrusions 27 , there is one which is larger . a direct consequence of this particularity is that if the transmissible torque is exceeded and the connection between the sleeve 26 and the second pinion 23 is lost , the protrusions 27 of the sleeve 26 must perform a full turn about their rotation axis , in order to reengage the seats 28 of the pinion 23 . this ensures that synchronization is maintained between the corresponding parts of the distribution unit 1 and in particular that the quincuncial layout of the plants in the soil is not altered . [ 0034 ] fig1 and 4 illustrate more clearly the mechanical elements that control the opening of the cups 4 containing the plant species to be planted . such figures show that at the center of the carousel 3 there are two arms 32 , 33 which lie one above the other , are rigidly coupled to the sleeve 12 , and are mutually angularly spaced . the arms 32 , 33 are substantially l - shaped , since each one is composed of a first horizontal portion 32 a , 33 a , which is substantially radial , and of a second vertical portion 32 b , 33 b , which is perpendicular to the first horizontal portion 32 a , 33 a . the arms 32 , 33 are adapted to abut against respective rollers 34 which are mounted so as to be laterally rigidly coupled to the half - cones 4 a of the cups 4 . the second portions 32 b , 33 b abut periodically , at each turn of the carousel 3 against the rollers 34 of the cups 4 which move together with the carousel 3 . in this manner , the arms 32 , 33 act as cams for the rollers 34 . when the rollers 34 encounter the arms 32 , 33 , they pass over and beyond them , imparting the opening movement to the half - cones 4 a . in turn , the half - cones 4 a lift the half - cones 4 b , since they are connected thereto by way of lobe - shaped portions 35 which affect the region proximate to the articulation pivots 5 . in this manner , the two half - cones 4 a and 4 b open together , dropping the plant that they contain into the respective underlying conveyance channels 6 and thence into the chamber 7 defined inside each one of the two hollow plowshares 8 that form a furrow in the soil . in particular , the rollers 34 are mounted on the half - cones 4 a at different heights ; more specifically , six of the twelve half - cones 4 a are connected to said rollers 34 in a raised position with respect to the remaining ones , since spacer arms 36 are interposed on the former . it should be noted that the half - cones 4 a that have the spacer arms 36 are alternated with the half - cones that do not have them along the circumference of the carousel 3 . moreover , the respective ends of the portions 32 b and 33 b of the arms 32 and 33 are at different heights inside the carousel 3 . since the rollers 34 and the portions 32 b , 33 b are arranged in this manner , it is evident that only the highest vertical portion 32 b is adapted to open all and only the half - cones 4 a provided with said spacer arms 36 , while the remaining half - cones 4 a are opened only by the lowest portion 33 b . this solution allows to open one half of the cups 4 with one arm 32 and the other half with the other arm 33 , and it is also possible to provide equal timing gaps between the events for opening the cups 4 on the opposite sides of the carousel 3 , allowing to provide arrangements of plants arranged in a quincuncial pattern , i . e ., arranged along mutually staggered rows , by using the same carousel - type distribution unit 1 . as clearly shown in fig4 and 5 , each ejector foot 10 has a profile which is generally c - shaped , with a contoured lower end 10 a . the end 10 a is adapted to delicately plant the plants that arrive from the conveyance channel 6 , while the upper end 10 b is rotatably articulated to a pivot 37 for connection to the frame 2 . each one of the two ejector feet 10 is further connected , in a central position , to a linkage 38 which makes it move with a reciprocating curved motion centered on the pivot 37 . the linkage 38 is arranged between said central portion of the ejector foot 10 and a pivot 39 of a crank 40 . the cranks 40 are arranged at the opposite ends of an auxiliary shaft 41 ( see fig2 ) which can rotate on bearings 42 accommodated in respective seats of the frame 2 . the auxiliary shaft 41 is substantially parallel to the shaft 18 and is driven thereby by means of the cylindrical gear 20 , which meshes with a respective cylindrical gear 43 being keyed in the central portion of the auxiliary shaft 41 . as shown in fig5 the ejector foot 10 further actuates the dispensing of the microgranular weed and pest control agent contained in the funnel 44 of a dispenser 45 . the ejector foot 10 is rigidly connected , proximate to the pivot 37 for articulation to the frame 2 , to a rocker 46 acting on a rod 47 , in turn connected to a plate - like valve 48 which controls the outflow of the weed and pest control agent from a lower part 45 a of the dispenser 45 . the plate - like valve 48 has , across its thickness , a through hole 49 of presettable volume , in which a dose of weed and pest control agent is arranged . the valve 48 moves with a reciprocating rectilinear motion between a first position , in which the through hole 49 is aligned with a duct 50 that exits from the funnel 44 , containing the weed and pest control agent , and a second position , in which the through hole 49 is aligned with an inlet 51 of a tube 52 for conveying the weed and pest control agent onto the soil . in this manner , the dose of weed and pest control agent required to protect each planted plant is alternately loaded and released inside the through hole 49 . it has thus been shown that the invention achieves the intended aim and objects . the invention thus conceived is susceptible of numerous modifications and variations , all of which are within the scope of the appended claims . all the details may further be replaced with other technically equivalent ones . in practice , the materials used , as well as the shapes and dimensions , may be any according to requirement without thereby abandoning the scope of the protection of the appended claims . the disclosures in italian patent application no . bo2000a000490 from which this application claims priority are incorporated herein by reference .
a carousel - type distribution unit for handling and planting vegetable species , the carousel containing a plurality of conical cups , each whereof is composed of two half - cones which are articulated about substantially horizontal axes , the cups being adapted to contain the vegetable species and to open in order to plant them , the unit further comprises two arms which are fixed to the center of the carousel and are adapted to open two of the cups in order to release the plant species into two respective conveyance channels for guiding into respective internal chambers of respective hollow plowshares , from which the plant species are expelled by respective ejector feet into the furrows of the soil provided by the plowshares and arranged along two mutually staggered adjacent rows .