SE182103C1

SE182103C1 -

Info

Publication number: SE182103C1
Authority: SE
Publication date: 1962-01-01

Description

Uppfinnare: D L Whitmore Prioritet begtird frdn den 26 mars 1959 (USA) Foreliggande uppfinning hanfor sig till en cylindrisk fras, omfattande ett huvud, som i sin periferi har ett flertal spar, vilka stracka sig frail huvudets framsida till dess baksida och bilda mellanpartier mellan intilliggande spar, insatta frastander, vilka hava skaft, som aro anbragta i sparen och inneslutna av sparens bottenvaggar och sidovaggarna hos intilliggande mellanpartier och med hu.vuden forsedda fasthallningsskruvar, som stracka sig genom skaften och aro inskruvade i med gangor f8rsedda oppningar i huvudet vid sparens bottnar. Inventor: DL Whitmore Priority Started March 26, 1959 (USA) The present invention relates to a cylindrical phrase comprising a head having in its periphery a plurality of grooves which extend from the front of the head to its rear and form intermediate portions between adjacent grooves, inserted spacers, which have shafts, which are arranged in the grooves and enclosed by the bottom cradles of the grooves and the side cradles of adjacent intermediate portions and with head-provided retaining screws, which extend through the shafts and are screwed into openings in the heads of the grooves provided with passages. .

Huvudandamalet med uppfinningen är att astadkomma en fras av denna art, som har ett storre antal tänder an som hittills i prakliken varit mojligt att anbringa och som kan justeras ph ett lattare och snabbare satt. Detta ernas enligt uppfinningen vasentligen därigenom att fasthallningsskruvarnas gangor liksom oppningarnas hava en tryckflankvinkel, som icke vasentligt overstiger desammas statiska friktionsvinkel for forminskning av fOrskjutningen av de intilliggande vaggar, som innesluta en intilliggande tand, da. en fasthallningsskruv for en tand itdrages eller lossas. The main object of the invention is to provide a phrase of this kind, which has a larger number of teeth which hitherto in practice has been possible to apply and which can be adjusted to a lighter and faster set. This is achieved essentially in that the passages of the retaining screws as well as the openings have a pressure flank angle which does not substantially exceed their static friction angle for reducing the displacement of the adjacent cradles enclosing an adjacent tooth, da. a retaining screw for a tooth is tightened or loosened.

Uppfinningen skall nedan narmare beskrivas under hanvisning till pa bifogade ritning visade utforingsexempel. I fig. 1 och 2 visas frontvyer av en ph utsidan skarande fras fOr skarning av de konkava sidorna hos kuggar, respektive en pa insidan skarande fras fOr skarning av kuggarnas konvexa sidor. I fig. 3 och 4 visas radiella snitt efter linjen 3-3 i fig. 1, resp. efter linjen 4 1 1 fig. 2. I fig. 5 visas i stOrre skala ett parti av ett snitt genom en frastandfasthAllande skruv och den intillliggande delen av frashuvudet. I fig. 6 visas en lficnande vy genom en fras av konventionell typ. I fig. 7 visas en sidovy av en konventionell »hogergangad» fras, som har en pa utsidan skarande tand. I fig. 8 och 9 visas liknande sidovyer av en »hoger-» resp. »vanster gangad» fras enligt den fOreliggande uppfinningen. The invention will be described in more detail below with reference to exemplary embodiments shown in the accompanying drawing. Figs. 1 and 2 show front views of a ph outside cutting phrase for cutting the concave sides of teeth, and an inside cutting phrase for cutting the convex sides of the teeth. Figs. 3 and 4 show radial sections along line 3-3 of Fig. 1, respectively. along the line 4 1 in Fig. 2. In Fig. 5, on a larger scale, a portion of a section through a spacer holding screw and the adjacent part of the milling head is shown. Fig. 6 shows a similar view through a phrase of the conventional type. Fig. 7 shows a side view of a conventional "right-handed" phrase, which has a tooth intersecting on the outside. Figs. 8 and 9 show similar side views of a «hoger-» resp. "Left-handed" phrase according to the present invention.

Okningen av antalet tander i en fras är fordelaktig dels fOr kuggskarningsmaskinens produktionsformAga och dels fOr tandernas livslangd. Denna Caning resulterar emellertid i en minskning av bredden hos partierna mellan de tandupptagande sparen i frashuvuclet och i en reduktion av avstandet mellan intillliggande tandfasthallande skruvar. Sasom ett resultat harav minskas frasens styvhet, varjamte justeringen av tanderna forsviras. Vid nAmnda justering installes varje tand omkring frasen genom att man lossar den fasthallande skruven, varpa kilen installes och skruven &ter dragcs till. Lossandet och tilldragningen av skruvarna hava visat sig stOra laget av en tidigare installd bredvidliggande tand och ju mindre bredden hos det parti, som skiljer sparen at, ar och avstandet meiIan skruvarna gores, okas denna storning. Hittills har detta varit en begransande faktor i det antal tander, som det är mojligt att anordna i en fras med given diameter. The increase in the number of teeth in a phrase is advantageous partly for the production design of the toothed cutting machine and partly for the service life of the teeth. However, this caning results in a reduction in the width of the portions between the tooth-receiving grooves in the phrase hub and in a reduction in the distance between adjacent tooth-retaining screws. As a result, the stiffness of the phrase is reduced, and the alignment of the teeth is distorted. In the said adjustment, each tooth is installed around the phrase by loosening the retaining screw, installing the wedge and tightening the screw. The loosening and tightening of the screws have been found to be large in the case of a previously installed adjacent tooth and the smaller the width of the portion separating the grooves and the distance between the screws, this increase is increased. Heretofore, this has been a limiting factor in the number of teeth that it is possible to arrange in a phrase of a given diameter.

Styvheten av frashuvudet kan okas genom att utfora detsamma av genomhardat verktygsstal, vilket emellertid har fororsakat en annan svarighet: For att bringa en tand till fast anliggning mot frashuvudets frontyta gives tanden ett latt slag med ett lampligt verktyg just innan den fasthallande skruven Ater drages till. Vid hardade huvuden visar sig en I hog grad okad tendens for, att tanden, som aven bestir av hardat verktygsstal, studsar bort frau huvudet, da den utsattes fOr slaget. Man har funnit att dylika slag kunna utelamnas genom att lata fasthallningsskruvarna lute sa, att de, da de dragas till, draga ansatser pa tanderna mot huvudets frontyta. Detta okar emellertid den ovan namnda st8rningen av intilliggande tander. Denna effekt är egendomligt nog storm vid hifIgergangade» in vid »vanstergangade» frasar. Med hoger- 2— — gangad fras menas en fras, som roterar medurs sedd frhn baksidan. The rigidity of the milling head can be increased by performing the same of hardened tool steel, which, however, has caused another answer: To bring a tooth into abutment against the front surface of the milling head, the tooth is given a light blow with a suitable tool just before tightening the retaining screw Ater. In the case of hardened heads, there is a greatly increased tendency for the tooth, which also consists of a hardened tool, to bounce off the head when it is subjected to the blow. It has been found that such blows can be omitted by letting the retaining screws tilt so that, when tightened, they pull projections on the teeth towards the front surface of the head. However, this increases the above-mentioned disturbance of adjacent teeth. This effect is strangely enough storm at hifIgergangade "in at" vanstergangade "phrases. By right-handed phrase is meant a phrase which rotates clockwise seen from the back.

De ovannamnda ofordelaktiga effekterna hava eliminerats genom en kombination av tre sax-drag med resultat, att lattare justerbara, genomhardade frasar hava framkommit, vilka innehalla ett stone antal tander an som hittills varit mojligt. Dessa sardrag aro: a) lutning av fasthallningsskruvarna for dra()uncle av tanderna fast mot frashuvudets frontyta, b) anbringandet av de anslag, som trada i kontakt med frashuvudets frontyta pa de andar hos tanderna, som skulle rora sig mot frashuvudet, om tanden bringades att vrida sig i den riktning, i vilken densammas fasthallande skruv vrides for tilldragning och C) utfOrandet av tryckflankvinkeln hos gangorna tillnarmelsevis lika med den statiska friktionsvinkeln eller mindre. Utformningen av den forhattrade frasen enligt uppfinningen och det satt, pa -vilket dessa ire sardrag samverka far att uppna det onskade resultatet skall nu fOrklaras. The above-mentioned adverse effects have been eliminated by a combination of three scissor strokes with the result that easier adjustable, hardened phrases have emerged, which contain a stone number of teeth which has hitherto been possible. These features are: a) tilting the retaining screws to pull () uncle of the teeth firmly against the front surface of the froth head, b) applying the abutments which come into contact with the front surface of the froth head to the spirits of the teeth which would move towards the froth head, about the tooth was caused to rotate in the direction in which its retaining screw is rotated to tighten and C) the design of the pressure flank angle of the passages is approximately equal to the static friction angle or less. The design of the hated phrase according to the invention and the manner in which these features may work together to achieve the desired result will now be explained.

Den fras, som visas i fig. 1 och 3, är av Aogergangad» typ och omfattar ett huvud 10 av genomhardat verktygsstal med en konisk urborrning 11 for anbringande pa spindelnosen hos en kuggskarningsmaskin. En platta 12, somfast pd huvudet medelst skruvar 13, har ett sate 14 for huvudet hos en icke visad skru-v, som sakrar frasen pa spindeln. Rotationsaxeln for frasen och spindeln betecknas med 15. Frashuvudet liar omkring sin periferi ett flertal tandupptagande spar 16, som aro shilda medelst partier 17. Dessa spar aro ratvinkliga med sina motliggande sidovaggar belagna i parallella plan, som aro parallella med och lika fOrskjutna fran axellinjen 15. Eilar 18 aro anbragta ph sparens bottenvaggar. Dessa bottenvaggar luta nagot mot frasens axellinje, sasom visas i fig. 3, sa att kilarnas overytor 19 aro parallella med frasens axellinje. Bade kilytorna 19. och sparens bottenvaggar aro vinkelrata mot sparens sidovaggar. Brickor eller mellanlagg 21, som hava parallella ovre och undre ytor anligga mot kilarna. Bottenytor 22 pa skaft 23 hos frastanderna anligga mot brickornas ovre ytor. Tandskaftens sidor 24 (fig. 8) aro plana och parallella och std i kontakt med sparens parallella sidor, sh att de tatt inneslutas av dessa. Tandernas skarande partier 25 skjuta framat frau huvudet 10. Sasom visas i fig. 8 har vane tand ett anslag 26, som anligger mot front3rtan 27 hos huvudets intilliggande mellanparti 17. For det fall att frasen sasom visats är vhogergangath befinner sig anslaget pa tandens ledande eller framre ande. The phrase shown in Figs. 1 and 3 is of the Aogergangad type and comprises a head 10 of hardened tool steel with a conical bore 11 for mounting on the spindle nose of a toothed cutting machine. A plate 12, which is fixed to the head by means of screws 13, has a seat 14 for the head of a screw (not shown), which secures the cutter on the spindle. The axis of rotation of the cutter and the spindle is denoted by 15. The milling head lies around its periphery a plurality of tooth-receiving grooves 16, which are shielded by portions 17. These grooves are at right angles with their opposite side cradles located in parallel planes parallel to and equally offset from the shaft line 15. Eilar 18 aro fitted ph spares bottenvaggar. These bottom cradles are inclined slightly towards the axis of the phrase, as shown in Fig. 3, so that the upper surfaces 19 of the wedges are parallel to the axis of the phrase. Both wedge surfaces 19. and the saver's bottom cradles are perpendicular to the saver's side cradles. Trays or intermediate layers 21, which have parallel upper and lower surfaces abut against the wedges. Bottom surfaces 22 on shaft 23 of the abutments abut against the upper surfaces of the washers. The sides 24 (Fig. 8) of the toothed shaft are flat and parallel and are in contact with the parallel sides of the teeth, so that they are enclosed by them. The cutting portions 25 of the teeth protrude forward from the head 10. As shown in Fig. 8, the habit tooth has a stop 26 which abuts the front surface 27 of the adjacent intermediate portion 17 of the head. In the case that the phrase as shown is to the right, the stop is on the leading or front spirit.

Tanderna aro fasta i frashuvudet medelst fasthallningsskruvar 28, som stracka sig genom i linje med varandra belagna oppningar I tandskaften, mellanlaggen och kilarna samt aro ingangade i oppningar i huvudet. Skruvarnas axellinjer 29 ligga i radialplan, dvs. sadana plan som 3--3, vilka innehalla frasens axellinje 15. Dessa plan aro parallella med och belagna mitt emellan sidorna hos de ifragavarande sparen. Skruvarnas huvuden 31 anligga mot lutande ovre ytor 32 hos landskaften. Ytornas 32 lutning mot tandskaftens bottenytor 22 och den motsvarande lutningen av skruvarnas axellinjer 29 mot frasens rotationsplan an endast nagot storre an det som sakerstaller, att tanden drages bakat, da skruvarna 28 atdragas for astadkommande av, aft anslagen 26 tatt skola anligga mot frashuvudets frontyta 27. I praktiken anvander man sig av en lutning om ho grader. Tanderna installas radiellt i frashuvudet genom vridning av de kilinstallande skruvarna 33, som forflytta kilarna bakat och framat i sparen. Sasom visas aro de kilinstallande skruvarna 33 inskruvade i frashuvudet och sta i ingrepp med urtagningar 34 i kilarna. Skruvarnas 33 axellinjer ligga i samma radial-plan som axellinjerna 29 hos de tillhorande tandfasthallande skruvarna. The teeth are fixed in the milling head by means of retaining screws 28, which extend through openings in line with each other in the tooth shafts, the intermediate layers and the wedges and are inserted in openings in the head. The axis lines 29 of the screws lie in the radial plane, i.e. such planes as 3--3, which contain the axis line of the phrase 15. These planes are parallel to and coated midway between the sides of the spares in question. The heads 31 of the screws abut against inclined upper surfaces 32 of the shaft. The inclination of the surfaces 32 towards the bottom surfaces 22 of the tooth shaft and the corresponding inclination of the axis lines 29 of the screws towards the plane of rotation of the cutter is only slightly greater than that of the tooth being pulled back, as the screws 28 are tightened to abut the front surface 27 of the cutter head. In practice, a slope of about 0 degrees is used. The teeth are installed radially in the milling head by turning the wedge-installing screws 33, which move the wedges backwards and forwards in the grooves. As shown, the wedge-installing screws 33 are screwed into the milling head and engage recesses 34 in the wedges. The axis lines of the screws 33 lie in the same radial plane as the axis lines 29 of the associated retaining screws.

Sasom visas i fig. 5 hava de tandfasthallande skruvarna st8dgangor, som hava en tryckflankvinkel om sju grader och en bakre flankvinkel om fyrtiofem grader. Detta innebar, alt tryckflanken 35 bildar en vinkel A om sju grader i forhallande till en normal till skruvens axellinje och den bakre flanken 36 bildar en vinkel B om fyrtiofem grader med en dylik normal. Man liar funnit att genom anvandande av skruvar av denna art vid fOr ovrigt konventionellt utbildade frasar i stallet I Or vanligen forekommande skruvar, som hava den gangform, som visas i fig. 6, dar motsvarande -vinklar A' och B' ba.da aro trettio grader, en vasentligt mindre storning av intilliggande tander ager rum vid lossandet och atdragningen av skruvarna ehuru av skal, som senare skola angivas, delta arrangemang i sig sjalvt icke hell overvinner den ovannamnda svarighet, som sammanhanger med installningen av frasen. As shown in Fig. 5, the toothed retaining screws have support passages which have a pressure flank angle of seven degrees and a rear flank angle of forty-five degrees. This meant that the pressure flank 35 forms an angle A of seven degrees in relation to a normal to the axis of the screw and the rear flank 36 forms an angle B of forty-five degrees with such a normal. It has been found that by using screws of this kind in otherwise conventionally formed phrases in the stable I Or commonly occurring screws, which have the gait shape shown in Fig. 6, where the corresponding angles A 'and B' are a. thirty degrees, a substantially smaller disruption of adjacent teeth takes place during the loosening and tightening of the screws, although of shells, as will be stated later, delta arrangement in itself does not quite overcome the above-mentioned responsibility associated with the installation of the phrase.

Skillet till forbattringen ax- formodligen foljande: Da vinkeln A dr tillnarmelsevis lika med eller mindre an den statiska friktionsvinkeln for smorda stalytor ken en axiell belastning pa skruven, representerad av vektorn 37, icke overvinna motstandet av ytan 35 mot sidoforskjutning, varf5r vektorkraften 38, vilken i vent fall ar mycket liten, icke formar att fOrskjuta metallen i huvudet 10 omkring skruven i en tvargaende riktning, dvs. i riktning av vektorn 38. Refererande till fig. 1 framgar att om tvargaende spanningar 38", som harrora frau lossandet eller atdragningen av de tanclfasthallande skruvarna, aro sa sma, att de icke stracka sig till den mellanliggande zonen av huvudet mellan plan 39, som tangera zonen under intilliggande Under och omfatta mellanpartiet 17 mellan dessa, sit kunna dylika spanningar icke menligt inverka pa installningen av en intilliggande tand. Del- — —3 ta innebar, att ett lossande eller en atdragning av skruven a (fig. 1) cla icke paverkar laget av den tand, som fasthalles medelst skruven b. Uppenbarligen erhaller man en liknande reduktion av storningen pa intilliggande Under genom att anvanda skruvar, som hava en tryckflankvinkel, som ar mindre an sju grader, dvs. mellan noll och sju grader. Emellertid aro dylika skruvar svara att framstalla med erforderlig exakthet. The difference to the improvement is probably as follows: Since the angle A is approximately equal to or less than the static friction angle of lubricated steel surfaces, an axial load on the screw, represented by the vector 37, does not overcome the resistance of the surface 35 to lateral displacement, whereby the vector force 38, which in this case is very small, does not form to displace the metal in the head 10 around the screw in a transverse direction, i.e. in the direction of the vector 38. Referring to Fig. 1, it can be seen that if transverse stresses 38 ", which cause the loosening or tightening of the retaining screws, are so small that they do not extend to the intermediate zone of the head between planes 39, which tangent to the zone below adjacent Under and enclose the intermediate portion 17 between them, such stresses may not adversely affect the installation of an adjacent tooth.Part- - —3 take meant that a loosening or tightening of the screw a (Fig. 1) cla does not obviously affects the tooth, which is held by the screw b. Obviously, a similar reduction in the size of the adjacent Wonder is obtained by using screws which have a pressure flank angle which is less than seven degrees, i.e. between zero and seven degrees. such screws respond to manufacture with the required accuracy.

Vid vanligen forekommande skruvar (fig. 6), dar tryckflank- och bakre flankvinklarna A' och B' hada mycket overstiga den statiska friktionsvinkeln, overstiga de tvargaende krafter 38', som harrora frau axiella belastningar pa skruvarna 28', friktionsmotstandet av gangytan 35' mot sidoglende glidningsrOrelse, varfor en sidoforskjutning intraffar i det par- Iihuvudet 10', som Egger omedelbart om- kring skruvhdlen, da skruvarna lossas eller atdragas. Detta resulterar i spanningarna 38" (fig. 1), som stracka sig in i zonen mellan planen 39, sd att installningen av en land, som fasthalles av en intilliggande skru.v stores. In common screws (Fig. 6), where the compression flank and rear flank angles A 'and B' had greatly exceeded the static friction angle, the transverse forces 38 'exceeding axial loads on the screws 28' exceed the frictional resistance of the gang surface 35 ' against lateral sliding motion, whereupon a lateral displacement occurs in the pair head 10 ', which Egger immediately surrounds the screw handle, when the screws are loosened or tightened. This results in the stresses 38 "(Fig. 1) extending into the zone between the planes 39, so that the installation of a land held by an adjacent screw stores.

Fig. 7 visar en vy liknande den i fig. 8 men illustrerar en vanlig li.ogergfingad» fras, varvid anslaget 26' for anliggning mot frashuvudets 10' frontyta 27' befinner sig vid frastandens 25' bakre dude. liven axellinjen 29' hos fasthallningsskruven 28' ar parallell med ytan 27', dvs. ligger i frasens rotationsplan utan att luta mot detta sasom i fig. 1, 3 och 8. Dd en dylik skruv 28' aldrages genom att densamma vrides medurs, stravar det vridmoment, som harror Iran skruvhuvudets friktionsberoring att vrida tanden medurs, alt att krafter uppkomma, som verka mot partierna 17' mellan sparen och vilka angivas med pilar 39'. Genom matningar har man funnit, att dessa krafter minska breddimensionerna av intilliggande tandspar °ob. Oka bredddimensionerna 42' vid de motsatta andarna av dessa spar. Da frasen enligt fig. 7 modifierades sa, att skruvaxellinjen 29' lutade pa samma salt som axellinjen 29 lutar i fig. 3 for att draga anslaget 26' mot ytan 27' fann man, att forandringarna av dimensionerna 41' och beroende pa aldragningen av skruven i hog grad okades. Harav drog man den slut- satsen, att den okade kraften p. tanden i riktning av pilen 43' tillsammans med den motsatta motstandskraften, som utovades av anslaget vid 26', bildade ett kraftpar, som stravar att ytterligare vrida tanden medurs i huvudet och salunda akar krafterna 39', sa att darigenom storningen pa intilliggande tan-der okar. Detta resonernang ledde till den fOrbattrade frasen enligt fig. 1, 3 och 8. Fig. 7 shows a view similar to that of Fig. 8 but illustrates a common light-fingered phrase, the abutment 26 'for abutment against the front surface 27' of the friction head 10 being at the rear dude of the stand 25 '. the axis of the shaft 29 'of the retaining screw 28' is parallel to the surface 27 ', i.e. lies in the plane of rotation of the phrase without inclining to it as in Figs. 1, 3 and 8. If such a screw 28 'is never turned by turning it clockwise, the torque which causes the frictional contact of the screw head to rotate the tooth clockwise, until forces arise , which act against the portions 17 'between the spares and which are indicated by arrows 39'. Through feeds, it has been found that these forces reduce the width dimensions of adjacent tooth pairs. Increase the width dimensions 42 'at the opposite spirits of these grooves. When the phrase according to Fig. 7 was modified so that the screw shaft line 29 'was inclined on the same salt as the shaft line 29 is inclined in Fig. 3 to pull the stop 26' towards the surface 27 ', it was found that the changes of the dimensions 41' and depending on the age of the screw to a high degree okades. From this it was concluded that the increased force on the tooth in the direction of the arrow 43 'together with the opposite resistance force, which was exerted by the stop at 26', formed a pair of forces which punished to further turn the tooth clockwise in the head and salunda increases the forces 39 ', so that thereby the magnification of adjacent teeth increases. This reasoning led to the improved phrase of Figures 1, 3 and 8.

Refererande till fig. 8 resulterar atdragningen av skruven 28 i att tanden drages Mat I riktning av pilen 43. Detta tillsammans med den motstandskraft, som pafores anslaget 26 och som representeras av pilen 44 bildar ett kraftpar, som strayer att vrida tanden mot- urs i huvudet. Detta par fir motriktat och stravar darfOr att eliminera effekten av det motsatta kraftparet, som representeras av pi- larna 39, 39 och som harror frau vridmoment, som pafores genom friktion vid vridning av skruven 28. Mellanpartierna 17, 17 avlastas darfOr frau den storningskalla, som forklarats i samband med fig. 7. Referring to Fig. 8, the tightening of the screw 28 results in the tooth being pulled in the direction of the arrow 43. This together with the resistance force which is applied to the stop 26 and which is represented by the arrow 44 forms a pair of forces which stray to turn the tooth counterclockwise. the head. This pair is counterclockwise and strains to eliminate the effect of the opposite force pair, which is represented by the arrows 39, 39 and which harrows from torque, which is pafored by friction when turning the screw 28. The intermediate portions 17, 17 are relieved therefrom from the interference cold, as explained in connection with Fig. 7.

Kombinationen av de Ire sardragen a), b) och c), som oven angivits, resulterar salunda i frasar, som Oro lattare att justera an tidi- gare kanda frasar av i ovrigt liknande ut- formning. Denn.a kombination av sardrag ger det salunda mojligt att Oka det antal tinder, som kunna anordnas i en fras av given storlek utan att menligt inverka pa justeringsegenskaperna. Exempelvis ar den visade fra.- sen, som har en nominell diameter om ungefar 18,7 cm och dr forsedd med sexton -Lander, lattare att installa an en konventionell fras, som har samma diameter men endast tolv tander. The combination of the Irish features a), b) and c), as stated above, thus results in phrases, which Oro more easily adjusts to previous known phrases of otherwise similar design. This combination of features thus makes it possible to increase the number of peaks which can be arranged in a phrase of a given size without adversely affecting the adjustment properties. For example, the phrase shown, which has a nominal diameter of about 18.7 cm and is provided with sixteen -Lander, is easier to install than a conventional phrase, which has the same diameter but only twelve teeth.

Frasen enligt fig. 1 och 3 liar pa utsidan skarande tander, vars spetsig vinkel bildande sidoskarande eggar 45 beskriva en inre, konisk yta, da frasen roterar. En dylik fras anvandes for slutbearbetning av de konkava sidorna av koniska kugghjul med spiralskurna kuggar och hypoidkugghjul. Fig. 2 och 4 visa samma frashuvud 10, kilar 18, mellanlagg 21 och fasthallande och installande skruvar 28 och 33 men med pa insidan skarande -Lander 25", vars spetsig vinkel bildande sidoskarande eggar 46 utforma en yttre, konisk yta. Denna art av fras anvandes far slutbearbetning av de konvexa sidorna hos kugghjulen. Tandernas 25" skaft 23' hava samma form som skaften 23 och anslagen pa tanderna, svarande mot anslagen 26 i fig. 8, befinna sig aven pa tandernas 25" framre andar, eftersom tanderna Oro avsedda for en fras, som roterar medurs sedd bakifran. The phrase according to Figs. 1 and 3 shows on the outside intersecting teeth, the acute angle of which forms lateral intersecting edges 45 describe an inner, conical surface, as the phrase rotates. Such a phrase was used for final machining of the concave sides of conical gears with helically cut teeth and hypoid gears. Figs. 2 and 4 show the same milling head 10, wedges 18, intermediate layers 21 and retaining and installing screws 28 and 33 but with on-inside cutting -Lander 25 ", the acute angle of which forms side-cutting edges 46 forming an outer, conical surface. The 25 "shaft 23 'of the teeth 25' has the same shape as the shafts 23 and the stops on the teeth, corresponding to the stops 26 in Fig. 8, are also located on the front spirits of the teeth 25", since the teeth Oro intended for a phrase, which rotates clockwise seen from behind.

Fig. 9 visar tandformen hos en fras, som roterar moturs sedd bakifran. Har firo huvudet, mellanlaggen, kilarna och skruvarna exakt lika dem, som visas i fig. 1, 3 och 8. liven tandskaftet 23a har samma form som skaftet 23. Endast det skarande partiet 25a och laget av anslaget mot frontytan aro omkastade. I delta fall am anslaget, som betecknas med 26a, placerat pa tandens bakre i stallet f Or framre ande, sh att det vridmoment, som uppkommer, da. tanden drages mat genom atdragning av fasthallningsskruven, raotverkar det vridmoment, som pafores genom friktion medelst skruvarna, sasom f Orklarats under hanvisning till pilarna 43, 44 och 39 I fig. 8. Det am uppenbart, att man i stallet for att Andra laget av anslagen 26 och 26a mellan tandernas framre och bakre ande kan fOrse skruvarna 28 med vanstergangor i stallet for hogergangor. Till foljd av den store forvirring delta emellertid skulle fOrorsaka med hansyn till den nastan alltid fOrekommande — — anvandningen av hogergangade, tandfasthallande skruvar, ãr det lampligt, att skruvarna 28 hava hogergangor. Fig. 9 shows the tooth shape of a phrase which rotates counterclockwise seen from behind. If the head, the middle layer, the wedges and the screws are exactly the same as those shown in Figs. 1, 3 and 8. the toothed shaft 23a has the same shape as the shaft 23. Only the cutting portion 25a and the layer of abutment against the front surface are inverted. In this case, the stop, denoted by 26a, placed on the rear of the tooth in place of the front end, so that the torque which arises, then. the tooth is drawn by tightening the retaining screw, it affects the torque which is pafored by friction by means of the screws, as explained with reference to arrows 43, 44 and 39 in Fig. 8. It is obvious that instead of the Second layer of the stops 26 and 26a between the front and rear ends of the teeth can provide the screws 28 with left-hand passages instead of right-hand passages. Due to the great confusion involved, however, in view of the almost always prevalent use of right-handed, toothed screws, it is appropriate that the screws 28 have right-hand holes.

Claims

Patent claim:

Cylindrical phrase, comprising a head (10), having in its periphery a plurality of grooves (16), which extend the front of the Iran head to its rear and form intermediate portions (17) between adjacent grooves, inserted spacers, which have shafts ( 23), which are fitted in the rafters and enclosed by the bottom cradles of the rafters and the side cradles of adjacent intermediate portions and provided with retaining screws (28) extending through the shafts and screwed into apertured openings in the head at the bottoms of the rafters, the passages of the screws as well as those of the openings have a pressure flank angle (A) which does not substantially exceed their static friction angle for reducing the displacement of the adjacent cradles enclosing an adjacent tooth when a retaining screw for a tooth is tightened or loosened.

2. A phrase according to claim 1, characterized in that said passages are of the pillar type and that their pressure flank angle (A) does not substantially exceed seven degrees.

Phrase according to claim 1 or 2, characterized in that the side cradles of each spar (16) are parallel and perpendicular to the bottom cradle of the spar, each tooth has a stop (26) for abutment against the front surface (27) of the head and that the axis lines (29) of the screws ) lie in a plane (for example 3-3) parallel to and covered between the associated side surfaces and tilt at an acute angle to the associated bottom surfaces on such a salt that said abutment is drawn towards a straight angle of the head with the front surface (27) forming the axis of rotation (15) ) when tightening the screws, the abutments (26) being placed on the spirits of the teeth, which try to move towards the front surface of the head in the event of a torque in the direction used in the screws.

4. A phrase according to claim 3, characterized in that the toothed shafts, like the screws for the screw heads (31), have flat surfaces (32) which are perpendicular to the axis lines (29) of the screws.

5. A phrase according to claim 3 or 4, characterized in that inserts (18, 21) are arranged between the bottoms of the shafts and the bottom surfaces (22) of the shafts, the surfaces of said inserts which are in contact with the shafts being parallel to the axis line of the shank. (15).

6. A phrase according to claim 3, 4 or 5, characterized in that the planes (for example 3-3) in which the axis lines (29) of the screws lie contain the axis of rotation (15) of the phrase.

A spacer for insertion into the head of a cylindrical frieze, said head having a flat front surface (27) which is perpendicular to the axis of rotation (15) of the milling cutter, and around its periphery is provided with a plurality of grooves (16) extending substantially in direction of said axis line, characterized in that the tooth has a shaft (23), which comprises parallel side surfaces (24) for contact with the sides of a groove and a bottom surface (22), perpendicular to said side surfaces for contact with the bottom of the spire. and which shaft has a bore for piercing a toothed holding screw (28) for screwing into the milling head and also an upper surface (32) perpendicular to the bore for contact with the head of the screw (31), the shaft axis of the bore jigger in a plane ( for example 3-3) parallel to said side surfaces and inclined towards said bottom surface, so that the distance between the upper and bottom surfaces increases from the front of the shaft to its rear part and that the tooth has a shoulder (26) for abutment against the head said flat front surface, in which a torque is applied to the tooth in a clockwise direction, seen from the top of the tooth. Cited publications: U.S. Patent Nos. 1,969,843. Stockholm 1963. Kunz !. Boktr. P. A. Norstedt & Saner. 630089 GENERAL STABENS LITC