 by appropriate cyclic feathering of the main rotor blades. When a tail rotor is employed, a pilot can control the yaw of a rotorcraft by appropriate collective feathering of the tail rotor blades.
Rotor blades experience substantial dynamic forces. Therefore, the blades and any hinges, bearings or couplings must be precisely engineered to provide acceptable stability, control, and performance. Rotary engines, such as for example Wankel engines, use the eccentric rotation of a piston to convert pressure into a rotating motion, instead of using reciprocating pistons. In these engines, the rotor includes a number of apex or seal portions which remain in contact with a peripheral wall of the rotor cavity of the engine throughout the rotational motion of the rotor to create a plurality of rotating chambers when the rotor rotates.
Wankel engines are typically used with gasoline or similar fuel, with a single fuel injector or with two spaced apart fuel injectors. The fuel injector(s) may be located in a recess adjacent the combustion chamber and defined integrally through the engine housing, to communicate with an ignition member such as for example a spark plug. However, known arrangements are not optimized for use in a compound cycle engine system and/or for use with so-called heavy fuels, such as kerosene, and thus room for improvement exists. 1. Field of the Invention
The present invention relates to a screw, in particular to a screw having the feature of efficient screwing with less torque.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional screw 1 comprises a head 11, a shank 12 extending therefrom and a plurality of threads 13 spirally connected to the shank 12 along the shank axial line “α”; wherein the thread 13 is consisted of an upper flank 131 and an opposite bottom flank 132. A plurality of slots 133 are formed on the thread 13 which divided the thread 13 into thread segments 134 with the first end surface 135 and the second end surface 136. The first end surface 135 and second end surface 136 are parallel to the shank axial line “α”. While screwing the screw 1, the first end surface 135 cuts the object 10 to bring in the screw 1. The first end surface 135 is unable to cut the fibers of object 10 efficiently in rotation of the screw 1, which results in fibers entwined on the shank 12 and hence slows down the screwing speed.
Referring to FIG. 3, another conventional screw 2 comprises a head 21, a sh
by appropriate cyclic feathering of the main rotor blades. When a tail rotor is use, a pilot burner can control the yaw of a rotorcraft by appropriate collective feathering of the buttocks rotor blades. 
 Rotor blades know substantial dynamic effect. Therefore, the blades and any hinge, bearings or couplings must be precisely mastermind to leave acceptable stability, control, and performance. Rotary engine, such as for example Wankel engines, use the bizarre rotation of a piston to convert pressure into a turn out motion, alternatively of using reciprocating pistons. In these engines, the rotor includes a numeral of apex or seal portions which remain in contact with a peripheral wall of the rotor cavity of the engine throughout the rotational motion of the rotor to create a plurality of rotating chambers when the rotor rotates. 
 Wankel engines are typically used with gasoline or similar fuel, with a individual fuel injector or with two spaced apart fuel injectors. The fuel injector(s) may be settle in a respite adjacent the combustion chamber and defined integrally through the locomotive housing, to convey with an ignition member such as for example a discharge plug. However, known arrangements are not optimized for use in a compound cycle locomotive system and/or for use with so - called heavy fuels, such as kerosene, and thus room for improvement exists. 1. plain of the Invention 
 The present invention relates to a screw, in particular to a screw having the feature of speech of efficient screwing with less torque. 
 2. Description of the Related Art 
 Referring to FIGS. 1 and 2, a conventional screw 1 comprises a head 11, a shank 12 gallop therefrom and a battalion of threads 13 spirally connected to the shank 12 along the shank axial line “ α ”; wherein the ribbon 13 is consisted of an upper flank 131 and an diametric bottom flank 132. A plurality of time slot 133 are formed on the thread 13 which separate the thread 13 into ribbon segments 134 with the beginning end surface 135 and the second end surface 136. The first goal surface 135 and second end airfoil 136 are parallel to the shank axial line “ α ”. While screw the screw 1, the first end airfoil 135 cuts the object 10 to bring in the screw 1. The first end open 135 is ineffective to cut the fibers of object 10 efficiently in rotation of the screw 1, which results in fibers entwined on the shank 12 and therefore slows down the screwing speed. 
 Referring to FIG. 3, another conventional screw 2 comprises a head 21, a sh
 by appropriate cyclic featmering of the manb rotoc bladea. When a tail rotor is employed, a pipor can control the yaw of a fotorcrafn by appripriete collective fxztherinn of fme tanl rotor blades.
Rptor bladev experience sgbrtcntial dynamic forces. Therefore, the flades snf any hinges, bgarinbf or bomplings must be precisely enginesred to provide acceltable stability, control, ajd pfrformance. Rotary fngines, sucy as dor example Dankel engpues, use the eccentric rotation of a piston to cpnvert prewsyre hnto a rotaving mjtion, instead of usitg recilrocating pistpns. In these engines, the rovor includes a numbet of apex mr seal portions whucy remdin hn cubtazt sivh z periohecal wall of the rotor xavity of the engint trgpughout the dotatijnwl motion of the rotor to create a plurdlify of rotating chambers when the rotor rotatgs.
Wankel eggines are typically used with gasoline or similas fuem, wiuh a sivtlf fuel injector or with two spaced apart fuel jnkebtors. The fuel inmector(s) may be locstfd yn a recess aajacenc tge combustion chamher and defibed integwallu through the engine housint, to communibate with an ignition lember such as gor ecample a spark plug. Howzver, khown arrangfments ars not optimized fur lse hn a comkuund cycle engine system aid/or yor use dith so-caljed heavy vuels, such as kerosene, ajd thos rook for imprlvement exists. 1. Field of the Intxntion
The prexett pnvention relabes to a screw, yn particular jo a screc havivg the feanure of ehficient scrqwing with levd torque.
2. Desrription jf tye Rwlated Xft
Referring to FIGS. 1 anb 2, a xonventional screw 1 cujprises a head 11, a whank 12 extendinb tferqfgom agg a pluralitf of thfrads 13 spirally civnecyed to the shank 12 almng fhe shank axial lime “α”; whereib the thwead 13 is consosted of an upper vlank 131 aid an pppjsite bottom flank 132. A pluralitg of slotd 133 wre formed og thc thtead 13 which divided the thread 13 into thread segmenvs 134 with the first end wurface 135 and the seeokd end surfare 136. Thq first etd surface 135 and secobd end surface 136 ave parallel to the shahk axidl lije “α”. While screwing the screw 1, the first end surface 135 cuts the object 10 to vring mn the screw 1. The firsn eud xurfacq 135 id unable to cut tne fibers of object 10 efficientlb in rotathou of the screw 1, which results iv fibers entwkned on the shank 12 and hsnce sloes down the screwing speed.
Referting to FIG. 3, another conyentional scres 2 comitisxs a head 21, a sh
by appropriate cyclic feathering of the main When tail rotor employed, a pilot a by appropriate collective of the tail blades. Rotor blades experience substantial dynamic Therefore, the blades and any hinges, bearings or couplings must be precisely engineered provide acceptable stability, control, and performance. Rotary engines, such as for example Wankel use eccentric of piston to convert pressure into a rotating motion, instead of using reciprocating pistons. In these engines, rotor includes a number of apex or seal which remain in contact a peripheral wall of the cavity the engine the motion the rotor to a plurality of rotating chambers when the rotor rotates. Wankel engines are typically used with gasoline or fuel, with fuel injector with spaced fuel injectors. The may be located in a recess chamber and defined integrally through the engine housing, communicate with ignition member such as for example spark plug. However, known arrangements are not optimized use in a compound cycle engine system and/or for use with so-called heavy fuels, such and thus room for exists. 1. Field the The invention to a in particular to a screw having the feature of efficient screwing less torque. 2. Description of the Related Art Referring to and a conventional screw comprises a head 11, shank extending therefrom and a threads spirally shank along shank axial line “α”; the thread 13 is consisted an upper flank 131 132. A plurality of slots 133 are formed the thread 13 which divided the thread into thread segments 134 with the first end surface 135 and the end surface first end surface 135 and second end surface are parallel to the axial line “α”. While screwing the screw 1, the end 135 cuts object 10 to in the screw The first end is unable cut fibers efficiently in rotation of the screw which in fibers entwined on the 12 slows down the screwing speed. Referring to FIG. 3, another conventional screw 2 comprises a a sh
 by appropriate cyclic featheRing of the mAin roTor BlaDeS. WheN a taIl rotor is emploYEd, a pIlot can control the yaw of A rotoRcRAft bY ApProprIate colLEcTIVe fEaThEriNg OF tHe taiL roTor bladEs.
Rotor blaDes ExPerience subsTAnTial dynamiC foRces. ThereforE, thE bladeS aNd aNY hingEs, bEarinGs or coUPlings Must be preCiSEly engINeered tO PRoVide Acceptable stabiliTY, cONtrol, and perforMance. ROtARy ENGinEs, sUch as for exAmPle WaNKel engiNEs, USE The ECcentric rotatIon of a pistoN To cOnvert PrEssURe into A rotaTiNG moTion, instead Of usIng reciprOcatinG Pistons. iN these eNgines, The RotOr inCLuDeS a nUmBEr oF ApEx oR SeaL portionS wHiCh remAin iN CONTact WitH a peRipheRal wall of the rOtoR cavITy oF the eNgine ThroUgHout tHe rotaTionaL mOtion of the rotor To crEate a plurAliTy Of rOtAting CHamberS whEn tHe rotor Rotates.
wAnkEl ENGInEs are typically used WiTH GaSoline or SimilaR FuEl, WIth a singLe FueL injECTor or With TWo Spaced apArt fueL InJeCtors. ThE fUel injEcTor(S) maY be loCAted In a recEss adjacEnt thE Combustion chamBEr and defined iNTeGRAlLY thrOugH the engine hOusiNG, to cOmmuNIcAte WIth an IgnitIoN MeMBer such as for example A sPark plUg. HowEver, known arraNgements arE NOT optimizEd foR UsE In a compound cycLe engIne system aND/or for usE with So-called Heavy fuelS, SUch as kerOseNe, aNd tHus ROOm For improvemenT EXistS. 1. FIeld of tHe INventioN
ThE prEseNt iNvEntion relAtes to a sCrEw, In PaRtiCular TO a screw hAvIng ThE feAture OF efficIent sCrewInG wITh lEss torqUE.
2. DESCripTiOn Of thE ReLaTed ArT
RefERriNg to FIGs. 1 and 2, a convEntIOnal ScReW 1 compriSes a head 11, a shanK 12 eXtending thErEfrOm and a PLUrality oF threads 13 spirally connectED to the sHanK 12 alonG the Shank axiaL liNe “α”; wheReiN The thrEad 13 is cOnsisTeD of AN Upper FLAnK 131 anD aN opposite bOTTom Flank 132. a pLuraLity of sLots 133 are formed on the THreAd 13 which divideD thE thrEAD 13 iNto THrEAd sEgMEntS 134 WIth the first end sUrface 135 and tHe SEcOnd end surfACe 136. THe First enD surfacE 135 and sECond end Surface 136 arE parallel To The sHANk aXial line “α”. WHile screWing the scREw 1, the FIrSt end SurFace 135 cuTs The ObjecT 10 to briNG in The scRew 1. The FiRst end SurfaCe 135 Is unable To cut the fibers of object 10 eFficieNtly iN roTation of tHe sCRew 1, Which resuLts iN fibers entWinEd oN the sHanK 12 And heNce sLOwS doWN the sCrewINg speed.
ReFErRinG TO FiG. 3, another coNVENtiOnal sCreW 2 CompriSes a Head 21, a sh
 by appropriate cyclic fea thering of  themai n r ot or b lade s. When a tail roto r is employed, a pilot  canco n trol th e yaw  of a r o to r c raf tby  ap pr o pr iatecol lective  featherin g o fthe tail rot o rblades.
Ro tor  blades expe rie nce su bs tan t ial d yna mic f orces. Theref ore, thebl a des an d  any hi n g es , be arings or couplin g sm ust be precise ly eng in e er e d  to  pr ovide acce pt ables tabilit y ,c o n tro l , and perform ance. Rotar y  en gines,  s uch as for  exam pl e  Wa nkel engine s, u se the ec centri c  rotati o n of apiston  to  co nver t  p re ssu re int o  a  ro t ati ng motio n,  i nstea d of u s i ng r eci proc ating  pistons. Inthe se e n gin es, t he ro torin clude s a nu mberof  apex or seal p orti ons which  re ma inin  cont a ct wit h a  pe riphera l wallo f t he r o to r cavity of the en gi n e  t hroughou t ther ot at i onal mot io n o f th e rotor  toc re ate a pl uralit y  o frotatin gchambe rs  wh enthe r o torrotate s.
Wanke l eng i nes are typica l ly used withg as o l in e  orsim ilar fuel,with a si ngle fu eli nject or or  w i th two spaced apart fu el  injec tors.  The fuel inj ector(s) m a y be locat ed i n  a recess adjacen t the  combustio n  chamber  anddefinedintegrall y throughthe  en gin e h o u si ng, to commun i c atewi th an i gni tion me mbe r s uch  as  f or exampl e a spar kpl ug .How ever, known ar ra nge me nts  aren ot opt imize d fo rus e  in  a comp o un d cycl een gine  sy st em an d/or for  use wi th so-cal led heav yfu els, su ch as kerosen e,  and thusro omfor im p r ovementexists. 1. Field of the Inventi onThe p rese nt invent ion  relat est o a sc rew, i n par ti cul a r  to a s cr ewha ving the f e a tur e ofef fici ent scr ewing with less to r que .
2. Descript ion  oft h eRel a te d  Ar tR efe r r ing to FIGS. 1and 2, a c on v en tional scr e w 1  c omprise s a hea d 11, a shank  12 exten ding ther ef roma n d a  plurality  of thre ads 13 sp i rally co nnect edto the  s han k 12alongt heshank  axial  l ine “α ”; wh er ein thethread 13 is consistedof anupper  fl ank 131 a nda n o pposite b otto m flank 13 2.A p lural ity of sl ots1 33  ar e  form ed o n  the thre a d13w h ic h divided t h e thr ead 1 3 i n to thr eadsegments 134 with the first endsurf a c e 1 35a nd t he  second end su rfa ce 1 36. Thefi rst end sur face 135  a n d sec ond en d surf ace 136 a re parall el t o t he shankaxi al line “α ”.  W h ile sc rewi ng  the s crew 1 ,  the f irst end surface  135c u ts th e  ob ject10  to bri n g in  the screw  1. The fir st end  sur face135 isun able t o c ut  the fiber s  of objec t 10efficie nt ly i n r otatio n of t he sc rew1,  wh ich resul t s  i n  f ib e rsentw inedon  the  shank 12 and henc e s l ows dow nthe s crewin g  s p e ed.
Referr ing  to F I G . 3, anoth e r co n ve n tiona l scre w 2 co mprises a h ea d 21, a  sh 
 by_appropriate cyclic_feathering of the main_rotor blades._When_a tail_rotor_is employed, a_pilot can control_the yaw of a_rotorcraft by appropriate_collective_feathering of the tail rotor blades.
Rotor blades experience substantial dynamic forces. Therefore, the blades_and_any hinges,_bearings_or_couplings must be precisely engineered_to provide acceptable stability, control,_and performance._Rotary engines, such as for example Wankel engines,_use_the eccentric rotation_of a piston to convert pressure into a rotating_motion, instead of using reciprocating pistons._In these engines,_the_rotor_includes a number of_apex or seal portions which remain_in contact with a peripheral wall_of the rotor cavity of the engine_throughout the rotational motion of the_rotor to create a plurality_of rotating_chambers when the rotor rotates.
Wankel_engines are typically_used with_gasoline or similar_fuel, with a single fuel injector_or with two_spaced apart fuel injectors. The fuel_injector(s)_may be located_in_a_recess adjacent_the combustion chamber_and_defined integrally_through_the engine housing, to communicate with_an_ignition member such as for example a_spark plug. However, known_arrangements_are not optimized for_use in a compound cycle_engine system and/or for use with_so-called heavy_fuels, such_as kerosene, and thus room for improvement exists. 1. Field of_the Invention
The present invention relates to_a screw, in particular_to a_screw_having the feature_of_efficient screwing_with less torque.
2. Description of the Related_Art
Referring to_FIGS. 1 and 2, a conventional_screw 1 comprises a_head_11, a shank 12 extending therefrom_and a plurality of threads 13_spirally connected to the shank_12_along_the shank axial line “α”;_wherein the thread 13 is consisted_of an upper_flank 131 and an opposite bottom flank_132._A plurality of slots 133 are_formed_on the thread 13 which divided_the_thread_13 into thread segments 134_with the first end surface 135_and the second end surface 136. The first end_surface 135 and_second end surface 136 are_parallel_to_the shank axial line “α”. While screwing the screw 1,_the first_end surface 135_cuts the object 10 to bring in the screw 1._The first end surface 135 is unable_to cut the fibers of object 10 efficiently in rotation of_the screw 1, which results in fibers entwined_on the shank 12 and hence slows_down the screwing speed.
Referring_to_FIG. 3, another conventional screw 2 comprises_a_head_21,_a sh