CA1315916C - Method of machining an oblong workpiece and a machine for performing the method - Google Patents

Abstract

A method of machining an oblong workpiece and a machine for performing the method Abstract A method of machining an oblong workpiece (18), which is placed substantially radially in a holding ring (1) and is deformed by cooperation with a roller (8) rotating in the holding ring. In connection with machining of a relatively large amount of material, the workpiece is caused to cooperate with a plurality of differently shaped areas (16) on the surface of the roller. The method is performed by means of a machine which comprises a rotating holding ring for substantially radial retention of the workpieces. The machine comprises a rotating roller which is placed inside the holding ring and is adapted to machine the radially inwardly directed end (17) of the workpieces. At least two differently shaped types of the machining areas (16 and 41) are provided along the surface of the roller, said areas being so disposed that the various types are present radially opposite a workpiece in a predetermined succession at least at the same time as the holding ring performs a correspond-ing number of entire revolutions.

Description

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A method of machining an oblong workpiece and a machine for performing the method The invention concerns a method of machining an oblong workpiece, which is placed substantially radially in a ring-shaped tool and is deformed by cooperation with a rolLer rotating in a holding ring.

The Danish Patent Specification 143 9~5 discloses a maohine for machining oblong workpieces and comprising a rotating holding ring for substantially radial retention of the workpieces, and comprising a rotating roller which is mounted within the tool and is adapted to machine the radially inwardly directed end of the workpieces. This known machine has been a great success for producing nail heads on nail workpieces. Therefore, it has been attempted to produce as many variants of nails as possible by means of this known internal rolling principle. However, it has been found that problems arise when a relatively large amount of material per workpiece is to be machined, i.e. deformed. Examples of such workpieces may be roofi~g nails or screws.

25~ The object of the invention is to provide a method of ~the present type which makes it possible to machine a larger~amount of material per workpiece than the prior a~rt. ~ ~

~Thls ob~ject is achieved~by performing~the method as stated in the characterizing portion of claim 1, wherein a first t~reatme~nt may comprise movlng th~e workpiece material, and~one or more subsequent treatments may comprise the f~lnal shap~ing. When the method is performed as stated ~5~ in claim~2,~an upsetting will result, so that the end ; of the workpiece to be treated will have a modified diameter~to length ratio, and when the method is perform-:: : : : _ ~ - ... .
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ed as stated in claim 3, shearing of material transverse to the longitudinal direction of the workpiece can be obtained.

When the possibilities provided by the method as defined in claims 1-3 are combined, there will be so much freedom in shaping the workpieces that the access angle between the holding ring and the roller is considerably less critical than is the case in the prior art. The method can moreover be performed no matter whether the peri-pheral speeds of the holding ring and of the roller are the same, but i.a. to reduce wear it is preferred to perfo~rm the method as stated in~claim 5.

15~ T~he~method of the~invention has special relation to the m~entloned~machining by rotatlng mov~ement. Thus, it is kno~n~ to forge a head on a;nail in~two working operations to~;~av~o~id~problems because of~;the limited Flow rate of the material. However, the flow rate is~no problem, ~either 20~ in the known machine~ or in the~pre~sent~;method where~the ma~chi~n~ing rate of the material~is~a~lready relatively low bec~a~use of the rolling movement.

The~varlous machlfi~ing areas;a~re preferab~ly distributed 25~ on~or~in;th~e surface~of~the roller, as stated in claim 4,~a~nd~when~the method is performed as stated in claim 6/~ th~e~wo~rkp~leces can~be~lntrod~uced~lnto the;hold1ng r~ing~ n~a~ve~ry~simple manne~r. I~n~m~any~u~ses,~there will he~J~u~st~two-dl;fferent~m~achln1ng~a~re~as~o~n~the roller, ;30~ w~hi~ch~ent~ai~1s~that t;he;~;~h~o~lding~must~b~e~adapted to~receive `an~o~dd number ol~ orkp~ in a;cc~or~d~an~e~wl~t~h ciaim~

Whe~n~ve~r~y~aGc~urate ma~chining~`~o~f~m~aterial is to be effected 35 ~ o~vér~a ~rel~ative~ly~;lar~ge~r~adi~al~ extent,~the shaping~areas ~ o~the-~rolle~r may have~dlfflou~lty~ln r~e1easing~the work-: : - .

3 ~31~16 piece. This problem may be avoided by performing the method as stated in claim 7. This method may e.g. be performed by means of tilting tools journalled in the roller, but these require relatively much space;
however, it will be appreciated that iF e.g. two or three different machining areas are present on the roller, only the second or the third machining area is to comprise a tilting tool. Therefore, it is sufficient to have a limited number of tools so that these do not reduce the strength of the roller.

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The invention also concerns a machine of the type which ~ ~ is de~scribed in the above-mentioned Danish patent speci-;~ ~f1cation. This nnachine is characterized by the features defined in the characterizing portion of claim 8.

~15~ n a pre~ferred embodiment, the first type of machining area is ~arranged as appears~from the claim 9, which re-sults in~ upset~ting of t;he workpiece. The embodiment of the ca~vit1~es def1ned in claim lO provides a volume of material as~great as possible of the upset material~, without this causing problems when the cavity releases the workpiece.
To obtain~lateral shearing of the material, the cavity m~ay~be offset, as appears from claim ll, and claim 12 de~f~ines~a~n~al~ternative embodiment for machining areas which~c~a~n~-bring about shearing of ma~terial transverse 25~ to~the;~longitudinal direct1on of the workp1ece.

's~menti~oned bèfor~e,~th~e~;;per1~pheral spe~eds~oF th~e~roller and~o;f~the~ho1~ding~r1ng~may~ be~the s~ame~or di;fferent, wh~ic~h i~s~wi~th~in the~sco~pe~of~the~subjéct-mat~ter of claim 1;3~. The~gear;t`ransm1ssi;on~l~s~adapted~i.a.~the diameter of:~t~he~'roLl~ert~the~inte~r~na~ d;~amete~r of the holdi~ng ring, th~e~numbe~r~`o~f~various machining~are`as as well as the num~ber~o~f groups of mach1~ni~ng~are~a~s~on`the roller, and t~;wi1~ be~appreclated~that the n~;ext~machining area in a ser~1es~oF~tre~atments of o~given workpiece is not , - ' ~ ' ' - `~
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necessarily located in adjacent groups of such areas.
Thus, the mentioned parameters may be varied in many ways. It has been mentioned before that the workpiece material may be moved by means of the position of the machining area on the roller, but it will also be appreciated that movement of the workpiece material may be provided through a difference between the ~aripheral speeds of the roller and of the holding ring.

lû Of course, it is possible in principle to introduce nail workpieces at any time into the rotating holding ~ring, but by means of the features defined in claim 14 this may be done with a firmly mounted station, while continuously feeding workpiece material to the station.
lS~ This~avoids discontinuous and reciprocating movements when~the workpieces are introduced.

C~1aim 15 deFines~some features of the preferred embodiment, while claim 16 defin~es an alternative embodiment of 20;~ th~e~machining areas~on the roller. This~ embodiment entails that shaping is possible over a relatively largè radial ext~ent~.~The machining area can therefore readily release ; the workpi~ece and acc;ordingly provide exact shaping and;~thu~s be adapted to e.g. calibration, as is stated 25;~ in~cl~aim 17. Then, e.g. c~ross slots may~be ca;librated n~scr~ews;, where the~screw~head and at least an initial machin~ing~of the slot~may have been performed in one o~r~ mo~re~preceding work~in~g operations.~

O~Ihe~1nv~n~t1~n~w111 be~exD~la1ned~more fu1ly below w1th r~e~fere~nc~e~t;o~the~drawl~ng~ n~:wh~i~ch ~

fi-g~ sho~ws~a machi~ne ~oF~a~know~n~type~on wh~ich~the manufac~turing principle acc~ording to the invention is ~b r~

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-fig. 2 is a sectional view along the line ll-l~ of the machine illustrated in fig. 1, fig. 3 is a section of a preferred embodiment of a holding S ring for cooperation with the roller of the invention, fig. 4 shows a preferred embodiment of the machine of the invention, fig. 5 is a sectional view of the holding ring shown in fig. 3 and illustrates a locking mechanism adapted thereto, fig.~ 6 is a side view of a preferred embodiment of a roller of the invention, :
flg.~7~sh~ows the cooperation oF the roller illustrated n ~flg.~6 with a holding r1ng, ~flg~ 8 shows;~a sec~tion ~of the roller;and illustrates a~ prefer~re~d~embodimen~t of a machinig area provided in ~this, ~ ~ ~

f~lg.:~ 9 shows another embodiment of the roller of the ;~invent~l~on~which is here~provided with tilting tools, ; and,~

nfig.~lO~shows a section~of a third~ embodiment of the rol~l~e`r,~se;en From~the~ side, and~ llustrates a cavity for~:mach~l~nlng a~workplece~transvers~e~l~y~to the~Feeding directlon.~

A ~a~ t; 15 II~UStrSt~d ~n ~ ~5. 1 and 2 on ahlch mao~h~ine~ and~thus~on~which~ma~chin~ing principle the in~ent;lOn I~based.~

Such~a mach-ns ls k n O W n ~ F rom~ t~he~Da~nish Patent . ,,, ,:: ~ ~ .: . , '~ ' " ' ' ' ~31~6 Specification 143 935 and is unique in that the workpieces are machined by so-called internal rolling. Fig. 2 shows a vertical cross-section through the machine shown in fig. l, and it will be seen how the holding rings l form part of the other constructional members of the machine.
It appears that the machine is supported by two opposite plates 2 and 3, the plate 2 being stationarily secured to a given base, the plate 3 being pivotally mounted directly opposite the first-mentioned plate. The inner side of each of these plates mounts a bearing consisting of an inner ring 4 and an outer ring 5, the outer rings being secured to the inner rings 4 of the said bearings, one of said inner rings, viz. the one disposed in ~ ~ ~conn~ection with the stationary carrier plates, being ~internally provided with a toothing~6, which is adapted to~engage with a gear wheel 39 mounted on the drive shaft of:~the ~motor.

n~oper~at~lon of the mach~ine, the motor drives the two 20~ opposed;~holding rings via the toothed inner ring in such a~;manner that the two opposed holding tools placed in s~aid rings indirectly~ engage each~other via the workpiece and 1n the vicinity of the'machining area, a workpiece ra;dially opposite a machining~area being retained in 2~5~ the~ tw~o opposed holding t;~ools.; When a workpiece is present n~thls~p~osition,~its head is deformed corresponding to~a~mou~l~d~cavity in~the tools fa~cing~the~ring centre, an~d th~e~workpiece is released from~the~holding tools af~t~er~comp~leted rolllng of the~h~ead;~because of the~mutual-3~0 -~ ly~incl~l~n~ed~positions of~the~hol~dl~ng~rings.~This nc~ nat;lon causes an~incr~éasin9~mut~ual~distance~between t~he~h;o~l~din~g~ r-ngs in~bot~h;~;;pe~r~lphe~r~a~ direct~ions away '`f~rom~ he po~sition of~th~e~machinlng~ar~ea~radially opposite a~wo~rk~p~lece~where the~greatest~di~star;ce occurs at the 35~ comm~on~ up~pe~r vertex of~t~he~holding~rin~gs diametrlcally oppo~sl~te sa~i~d~machining~area~ T;he~mutually inclined posl~ti~on;s~;of~the h~olding~rings~ are~a preferred, known .

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structure which involves simplification of the supply of workpieces and release of these after machining.

In the prior art, the workpieces are present in the holding rings less than an entire revolution, e,g, about 270~, but as will appear from the following, the known arrangement may be changed so that the S workpieces may be present in the holding rings more than one revolution, Fig. 3 illustrates a section of a holding ring 9 which is adapted for the machine, The holding ring is thus provided with a groove 10 adapted to receive a plurality of holding tools 11 with a plurality of various spacer tools 12 and 13 between each of these, said spacer tools being distributed according to a determined pattern and being moreover clamped in a direction toward the bottom of the groove, i,e, in 10 the axial direction of the holding ring. Thus, the spacer tools 12 and 13 firmly position the holding tools 11 in the circumference of the holding ring by means of wedge effect, since both the holding and the spacer tools are provided with side faces which cut a plane, defined by the holding ring, in lines which~ are parallel with a groove 14 formed in the face of the tool, It will thus be appreciated that the radial~pressuro forces occurring in this structure between the roller 8 and the roll path fo}med by the 15 holding~ tools 11 cannot be transferred to the other holding tools, disposed in the groove, in the entire circumference of the holding ring 9, ~; This~ constructlonal prmciple for the holding ring is importanl in connectlon with the new structure of the machine of the invention, because it is intended precisely for~ machining of workpieces where great ~: movements of material may be necessary. As mentioned before, the - -:

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8 ' 1 31 ~9~ 6 machine is to handle workpieces which are to undergo two or more machining processes, and this is particularly important when the mentioned great movements of material are to be provided, such as e.g. for nails, screws or S the like with large heads. To enable such deformations, the shaping according to the invention is divided into two or more sub-processes.

To produce workpieces in several process steps, the roller of the invention is therefore provided with mould cavities ~ adapted to the individual types of workpieces, like the ; ~ mentioned holding tools. These mould cavities move the workpiece material downwardly and sideways with respect to~the mould cavities of the holding tools prior to the ~ final rolling. Thls embodiment of the roller face will be de~scribed more fully below.

F~ig.~-4~is~an overall illustration of an embodiment of the~machine of the invention, and shows the novel ;0~ ~components. It will thus be appreciated;that this novel s~truc~ture involves considerably increased~fle~ibility in~the fields of use of~the machine since it is now posslble to satisfy many different shape~requirements thanks to various roller types and~/or holding tools.

It~should~be~mention~ed~that t~he~known machines~oF~this typ~é~are~preferably~;driven so~that the~holding rings and~th~e~as~sociated~roll~er~r~ota~te~with~different~p~eripheral sp~eed~sj~the speed o~f~th~é ro;l~ler~be~i~ng~pref~erably greater ~than~th~a~t~o~f~the~ho~lding~rl~ng.~The~reas~an~for~the~ ~
se~lectl~on~o~f such coact~ion~be~twee~n the~rol~ler~and the ;h~old~l~n;g~`ring~ s u~su~ally~tha~t,~aFt~er con~tàct~:~wlth the r~oller~ t~he~workpiece is to~be~subjected;to ac~tion in the~fee~dlng dlr~e;ctlon to obts~in;a~be;tter~ ~n~tial~shaping.

Howev~er,~ this~principle~;~is not re;q~u~ired in the machine of~t~hé inve~nt~ion. Ow~ing t~o t~he fac~t~ that two or mnre . ~. .. .. . ~ :

'- ~31~916 initial part treatments of the workpieces can be obtained with the machine of the invention, this peripheral speed difference is no longer a practical necessity, so that wear on the engagement faces is reduced considerably.
It has also been found to be easier to control the de-formation sequence, in particular when moving relatively large masses ûf material, which has been solved according to the invention by a special arrangement of the roller.

Thus, fig. 4 shows a preferred embodiment of the machine where the roller is provided with two different types of machlnlng areas which are alternately disposed with the same mutual distance, one machining area 16 being adapted to pre-shape the inwardly extending free portion ~of the workpiece, while the immediately following machining area is to perform the~final rolling, after wh~ich~ the workpiece is finished. ~

The~first machining area 16 is, as~appears from the flg;ure,~provided as a radially~lnwardly~extending cavlty 6~ whlch~is substantially in the-~for~m of a truncated cone~whose~axis coincides with a radlus~of~the roller.
T~h~e cavlty 16 has th~is shape because of the deformation se~qùence~which the free portion~ l7 of the workpiece l8 has,~where this portion 1~7 Is upset to the~said truncated cone shape by the deformation. It will be apprec;lated t~hat this; shape i~s advantageous because so m~uch~;ma~te~r~ia~ as~poss~lble is;;moved~radially outward~ly n~t~h~e~:holdlng rlng aft~er the; flrst~shaplng process.~
Wh~en~the~axia1 cross~-~se~ctio~n~of~the~up~se~t~wo~rkpiece head 20~Ls~na~rr;owed upwardly~, it~w~ill b~e~a~ppreciated that ;the~d~è~formation path~and~thus ~the~flowabili~ty~requirements a~re~redu¢~ed~ and at~th~e;~same~tlme~a~better filling of the~m~ould~cavl~ty 21 o~f;~the;hold~lng~to~ol is obta~ined.

Fi~g.~4~s~hows~a~starting~workp~ie~c~e~ 8~which is disposed , : , ' .

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in a position just before its free portion 17 is to undergo a first deformation process by coaction with the oppositely disposed cavity 16. The same workpiece is shown at 20 after upsetting. Since, as mentioned, this workpiece is to be subjected to a further process, it is to be moved with the holding ring another revolution while being still retained, so that the head 20 of the workpiece then undergoes the final machining via the roller face 15, whereby the head of the workpiece has been given its final shape and is finished. Then the workpiece is moved on for release from the holding rings. For this operation to be feasible, it is necessary to have a switch-ing mechanism which is so adapted that workpieces that have still not been finished are allowed to pass the 15~' rel'ease location and be moved with the holding rings wh~ e~being still retained up to the mentioned final roiling~process. This switching mechanlsm may be provided as~a~so-called ti~mer wheel 22 and a guide rail 23 co-operating with it.
~20 The~time~r wheel 22 is peripherally provided with notches 24 with~a mutual arc distance, which corresponds to the arc~len~gth between every second wo~rkpiece, externally on the holding rlng~,~said timer~ wheel belng rotated with ~25~a~ peripheral speed~correspondin~g to that of the holding ring.~

;The ~t~i~me~r~wh~eel ~2 is so geared with~respect to the p~osltl~on~s~of the work~p~leces~in th~e~holding ring that o ~the~ locklng~pawls~25, which ~ex;tend~radl~ally outwardly from~the~out~er~slde~of~the hol;dlng~r~ing to retain finished work~pie~ces~ Jill cont~act~a~r~elease~face 2~6 on the t~imer whee~ The~release~p~awl~25~1s hereby~forced outwardly and~'re~l~'eases~a~locking~dev~i~ce~;in~the~;holding ring, follow-35~ ing~w~hlc~h;the workpiece~ is~fl~na~lly;rel~eased by~a projectingm~eans~46. ~Upon~further~ rotation of t~he holding ring, ~ ' ' 131~91~

the pawl 25 is moved in its releasing position to the said, adjoining guide rail 23, which for this purpose is provided with two guide faces 27 and 28 displaced 5 in the radial direction of the holding ring. Thus, the locking pawl 25 leads into the radial innermost guide face 27 of the guide rail 23, whereby the locking mechanism is held in a released position forwardly to a feed device or guide pin 29, where a new workpiece is fed to the lû empty holding tool.

In contrast to the foregoing, workpieces which have just : undergone the first shaping process will be moved toward the timer wheel 22 in such a manner that the locking }
15 pawls 25 associated with these workpieces will be received ;in the notches 24 of the timer wheel, so that the work-; p~ieces are:still retained, and so that a guide pin 29 mounted for the purpose in a radial extreme position ~ on the locking pawl engages the said second guide f ace : 20 28 of the:guide rail, which causes the workpiece to still be locked in the further feeding to the final machining.

: ~The said locking mechanism 27, which is of known type, :: is illustrated in fig.5 and operates in that the locking 5~ pawl 25:, which is rotatably secured to a pin 38 and is biased via~a spring 39, can be forced radially into the holding ring, so that a locking eccentric 4û, provided ~in a s~lidably~journalled bushing, can be rotated to a n~on-locking position~where the locking pawl 25, likewise :a~fter~lnsertion:of:a workpiece,~moves~into its locklng po~sltlon.~

New~wo~:rkpieces are insert~e~d into ~the empty holding tools 1-:by~me~ans of:a feed device adapted for this ( a so-called :~manipula~tor)~:29j which, to ensure cor~rect insertion time, s~so: geare~d w~lth respect to the rotation of the holding - ring tha~t~insertion of a wo~rkpiece takes place precisely wil.h:lntervals;corrcsponding to the time fnr the passage . , '' ', ' ' , ' ' ., ': ~ ~ .: . ' 12 1 31 ~ 6 of twice the arc length between two workpieces.

It will be appreciated that workpieces are to be-inserted at a relatively great speed, which takes place by con-tinuous rotation of the holding ring. To arrest the work-piece at the insertion, a positioning roller 30 is provided, said roller being adjustable in connection with various workpiece shapes. This roller positions the workpiece radially a little too far inwardly to ensure : ~ ln sufficient material, and upon further rotation the work-; piece meets another, fixed positioning roller 31 whichis adapted for the Final, radial positioning of the work-piece before this is subjected to the first deformation.

15~ In~the~shown preferred~embodiment, the roller 8 is provided~with two different machlning;areas, so that the~total~number of ma;c~hining a~reas ln the~circum~ference of~the~roller~is an even number.~This~is~because the number of~workp~leces ln~ the~holdl~ng ri~ng may not be 20~ div~isible by multiple~of the number~ of various types of mac~h~inlng a~reas on~the roller~so~as~to ensure ~that the~individual workpiece in~t;he holding ring will be s~ubjected~to the correct shaping~process when returning to~the m~ach~ining area radially opposlte to this,~ which 5~ is~tantamoun~t to the roller~and the holding ring, after e~ac~h'~re~volution of the latter~, having;been displaced pr~ecise~ly~an~arc sect~ion corresponding to a multiple o~f~the~dist~ance between two~mach}ning~areas.

30~ lt~w~ kew~l~se~be~'a~ppreci~a~ted~ that~the ro~ller~may be `provl;d~ed-wlth ano~the~r~nomb~er~o~f~'var~lous~mschl~nlng~areas, i:n,~accor~danc~e~wlt~h ada~ptl~ng~t~he~ab~ove~-men~tloned~:proportion p~ b~et~w~een;machlnlng are~as and th'e~number o~f workpieces in~th~e ;hol~ding ring.~

n~ fig~ 6~, the roller 8 is i11ustrated as seen ~from the :; l~ : :: ~ :
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roller side, so that the mentioned mould cavities 16 and the roller areas 41 disposed between these are visible.

Fig. 7 shows an enlarged section of the roller 8, which corresponds in principle to the view of fig. 4, but the roller is here provided with a mould cavity 32 which differs from the above-mentioned cavity in that, when disposed radially opposite a workpiece, it is displaced lû a distance in the feeding direction, which entails that the mass of material upset by this is correspondingly moved ahead with respect to a plane through the axis ~ of the workpiece and the centre of the roller.

This structure of the roller counteracts the flowing of material otherwise occurring which causes the material to tend to be pushed in the direction opposite the feeding direct~ion, so that, after completed process, the distribution of the material will be disuniform. It is thus~possible to produce heads for oblong objects having a considerably improved size and~finish.

Fig. 8 shows another embodiment of the mould cavities ~of the roller. As will be seen,~the truncated cone shape ~25 ~ 16 and 32 has been replaced by a substantially paraboloid cavity 33. This sha~e is particularly advantageous since the natural flow of the material follows a paraboloid shape,~ so~that some of the frictional forces, which would otherwi~se;occur by upsettlng according to the above-~30 ~ment~ioned~cavities, will be~removed, which is importantin~connecti~on with the already great~flow of material in~the~process, and which, oF course,~reduces the~risk of~c~rac~ks~and ruptures in the~machined material. It also appea~rs~ as indicated at~42 in the figure, that the 35 ~ requirement in respect of the necessary cavity depth has been reduced. Io~avoid pressure or tearing impacts ~r~

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14 ~ 6 on the truncated cone material 20 when the cavity leaves the truncated cone, the cavity may be rounded, as indicated at 34, so as to ensure a correctly shaped and unaffected workpiece cavity 2û, while reducing wear on the roller.

Fig. 9 illustrates the principle of an alternative embodi-ment of the roller. The machining areas oF the roller are movable so that the contact face of the machining area from engagement with a workpiece is constantly disposed radially opposite said workpiece until the contact face of the machining face releases the workpiece machined This manufacturing method is possible in that the movable machining areas or so-called tilting tools 43 are arranged as circular discs which are journalled around their axis, somewhat radially~inwardly toward the roller centre at a~distance which is slightly smaller than the radius of the t~llting tool. Thus, part of the~circular tilting tool~protrudes radially from the roller periphery, said 20~ part,~viz. the màchining face 38, having bèen planed for ~engagement with an oppositely disposed workpiece. It will;be appreciated that the Face 38 may be provided with~different forms of stamping contours, such as a ~ ~ cutting tool fDr cutting slots on screws.
t~ wi;l~l likewlse be appreciated that the tllting tools may be so journalled in the roller that~there is spring mechanlsm (not shown) for biasing the tilting tools so t~ha~t these, after having released the~workpiece in 30~ question,~rotate~back to their~starting position shown a~t~37~

WIt~h~the above~mention~d ~tru;~u~ he~ thus provided a~roll~;er~which~entails~that the mach~ining area on the 35 ~tilt~ing~to~ol~s are capable~o~f perfo~rming longitudinal and; t~lansverse,~ translatory~movemen~ts slmultaneously, :

, ' ~ ~31~916 which, as mentioned, is of importance in the pIoduction of relatively deep stamping contours It will be appreciated that in addition to the tilting tools the roller may have other machining areas, which is symbolized in the figure by the presence of two workpieces between the workpieces cooperating with the tilting tools.

5 Fig. 10 shows another embodiment of the roller of the invention where the machining areas comprise mould cavities 45 which, in contrast to the above-mentioned cavities, serve to provide bending of the free portion of the workpiece in directions transverse to the feeding direction, following which the workpiece is subjected to final rolling. Such initial shaping is adapted to be used in connection with the production of objects having D-shaped heads, where the straight edge of the head is parallel with lO the feeding direction in the holding ring.
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Claims (17)

1. A method of machining an oblong workpiece, which is placed substantially radially in a ring-shaped tool and is deformed by cooperation with a roller rotating in a holding ring, characterized in that the roller is driven relative to the position of the workpiece in the holding ring so that each workpiece is caused to cooperate with a plurality of differently shaped areas of the surface of the roller.

2. The method according to claim 1, characterized in that the workpieces are subjected to a preliminary deformation in the form of upsetting of material in that the machining areas on the roller corresponding thereto are provided as mould cavities which extend radially inwardly toward the centre of the roller.

3. The method according to claim 1 or 2, characterized in that the workpieces are subjected to a preliminary deformation in the form of shearing of material transverse to a longitudinal direction of the workpiece.

4. The method according to claim 1 or 2, characterized in that the roller comprises a plurality of machining groups, each of which has a plurality of mutually different machining areas, and that the roller is driven relative to the position of the workpieces in the holding ring so that a workpiece is caused to cooperate with a predetermined succession of the various machining areas.

5. The method according to claim 1 or 2, characterized in that the roller and the holding ring cooperating with it are driven with the same peripheral speed.

6. The method according to claim 1 or 2, characterized in that the workpieces in the holding ring are distributed with the same mutual distance and in a number which is not divisible by the number of machining areas on the roller.

7. The method according to claim 1 or 2, characterized in that following one or more preceding machining processes the workpieces are subjected to final shaping by means of machining areas rotatably journalled in the roller, and that a machining area performs a substantially radial movement with respect to the holding ring, from engagement with the workpiece and until completed shaping.

8. A machine for machining oblong workpieces and comprising a rotating holding ring for substantially radial retention of the workpieces and comprising a rotating roller provided within the holding ring to machine the radially inwardly directed end of the workpieces, characterized in that at least two differently shaped types of machining areas are provided along the surface of the roller, said machining areas being so disposed and the roller driven so that the various types of machining areas are present radially opposite a workpiece in a predetermined succession at least at the same time as the holding ring performs a corresponding number of entire revolutions.

9. The machine according to claim 8, characterized in that a first type of machining areas on the grounds of such areas on the roller are provided as a mould cavity which extends from the periphery of the roller radially inwardly toward the centre of the roller, with a narrowed cross-section.

10. The machine according to claim 9, characterized in that said mould cavity is partly defined by a paraboloid-of-revolution wall.

11. The machine according to claim 9 or 10, characterized in that the equidistantly spaced mould cavities corresponding to the machining areas on the roller are displaced a distance forwardly with respect to the other machining areas of the roller so that an axis of the mould cavity through the centre of the roller is disposed in a plane displaced from the axis of the workpiece when the cavity is present radially opposite such a workpiece.

12. The machine according to claim 8, 9 or 10, characterized in that a second type of machining areas in the groups of such areas in the roller is provided as shaping projections having shaping faces which form an angle with a common radial plane for the holding ring and the roller.

13. The machine according to claim 8, 9 or 10, characterized in that the roller and the holding ring are driven by means of a gear mechanism, which has such a transmission that the roller is driven with a peripheral speed so adapted with respect to the positions of the workpieces in the holding ring that the workpiece is caused to cooperate with a predetermined succession of mutually different machining areas in the groups of such areas of the roller.

14. The machine according to claim 8, characterized in that a workpiece insertion station is provided radially opposite the holding ring, and that the station is adapted to insert workpieces at intervals extending over a plurality of workpieces in the holding ring corresponding to the number of mutually different machining areas on the roller.

15. The machine according to claim 14, characterized in that the roller is divided into a plurality of groups, each of which comprises at least two different machining areas along the surface of the roller, and that the holding ring is adapted to receive an odd number of workpieces.

16. The machine according to claim 8, characterized in that one of the machining areas in each group is provided as tilting tools having a tilting axis which is disposed outside the axis of the roller and parallel with it, the tilting tools corresponding to each of said machining areas being provided as roller sections movable in the radial plane of the roller.

17. The machine according to claim 16, characterized in that the machining area adapted for the final shaping consists of a tilting tool which is adapted to perform a final, calibrating function.