CA1264507A1 - Method of producing bodies of revolution - Google Patents

Abstract

ABSTRACT

A rotation body having different diameters along the length thereof is produced by: a) rotating a blank about the longitudinal axis thereof and working the rotating blank between two pressure zones to apply thereto a local pressure exceeding the flow limit of the blank material whereby circularly extending impressions of different diameters are worked into the blank, the pressure zones crossing each other; b) displacing the pressure zones relative to each other while applying the local pressure, one of the pressure zones being displaced in a direction at an angle to its longitudinal extension and to the longitudinal direction of the pressure zone it crosses and the points of crossing of the crossing pressure zones forming a geometric line at an angle with the longitudinal axis of the blank to be worked;
and c) displacing the blank in dependence on the geometric line and on the different diameters to be produced.

Description

~X64~;~37 The present invention is concerned with the production of ro-tation bodies.
More particularly, the invention relates to -the production of rotation bodies having differer.t S diameters along the leng-th thereof, as well as bodies of revolution having at least one groove or the like which extends substantially in the peripheral direction thereof and whose width, extending in the axial direction of the body of revolution, decreases towards the floor of the groove, wherein, during rotation of a blank about its longitudinal axis, a pressure which exceeds the yield point of the material of the blank is locally applied The previously known methods of that kind provided for impressing a shaped rib into the blank as it rotated, the width of the rib, as considered in the direction of forward feed motion, increasing from a minimum value to a maximum value and the height thereof also increasing. In other words, in order to produce for example a V-shaped groove, the previous method involved using a shaped rib which was impressed with its tip leading into the rotating blank, the rib increasing in width and height in the course of the orward feed motion.
The disadvantage of such a method o~
manufacture is that the fact that the tip of the shaped rib was impressed into the material cause the material to undergo hardening, and the hardened region had to be further deformed, so that corres-pondingly high pressures are required and overloading of the material and thus cracking thereof may very easily occur.
The aim of the invention is to avoid such disadvantages and to propose a method of the kind set forth in the opening part of this specification, which avoids further deformation of regions of the workpiece which have already been severely deformedO

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S~7 According to the invention, that is achieved in that the width of action of the pressure is reduced from a width corresponding - la -~ 4~ 7 to the width of the grsove to be prcduced at the p~ripheral surface of the blank, to the width of the floor of the groove to be produced, in accordan oe with the progressing depth of i~pression, wherein the reducti~n in the width of impression, with progressing depth of impression, is effected in accordance with the inclination of the walls of the groove.
That provides that it is only ever the regions which have been less deformed, that are subjected to further deformation, and extreme levels of hardening and consolidation of the material are avoided. In addition, deformation of the blanks in that way requires a smaller amount of energy. When producing screwthreads by means of the methcd according to the invention, in accordance with a further feature of the invention, it may be provided that the screwthread groove is impressed into a blank which is of the outside diameter of the desired screwthread. m e material which is pr-essed out of the screwthread grcove in that operation is displaced in the axial direction so that the finished screwthreaded pin or bolt is greater in length than the blank used for that purpose.
In relation to screwthreads, in particular trapezoidal screwthreads or the like, there is the advantage, when using blanks which axe of the outside diameter, that the material does not have to flGw up the flanks of the screwthread in ordex completely to build up the screwthread flights or ribs, which in certain circumstances can result in overloading of the material and cracking at the peripheral surface of the screwthread flights, but the material can ~nly flow axially, thereby ensurin~ that the screw-thread flights consist of solid material and cannot have any cracks or cavities which are covered by material which is displa oe d in an outward direction.
30Another aim of the invention is to provide an apparatus for carrying o~t the method according to the invention.

' ~LZ~

In an apparatus comprising at least one roller which co-operates with a ~o-operating pressure surfa oe and which is movable relative thereto, it is therefore proposed, in accordance with the invention, that the width of the sh~ped rib or ribs decreases in the direction of the relative movement between the roller and the co-operating pressure surface, and ~he height thereof increases.
That ensures that, when producing a peripheral groove or the like, the blank is first acted up~n, with the n2uui~um width of the gro~ve to be produced, w~ile the width of impression progressively decreases and he depth of impression increases in the course of production.
Another possible configuration of an apparatus for carrying out the method according to the invention provides that, in an apparatus comprising two rollers which can he driven in mutually opposite directions of rotation and of which at least one is provided with a raised shaped rib and between which ~here is a roll gap, in accordance with another feature of the invention the rib is of decreasing width and increasing height in the direction of rotation of the roller. Such an apparatus also ensures that the pressure firstly acts on the blank with the greatest width of the groove to be produced, and the widtJh of action decreases as the groove is impressed in the blank. In accordan oe with a further feature of the invention, it may be prc~ided that shaped ribs are disposed both on a drivable central roller and on the co-operating surfa oe which is subdivided into segments, which ribs cross each other in the oourse of the ~utual relative movement.
m ose features mQke it possible for the counterpressure surface to be advanced to a greater or lesser degree towards the central roller, as required, without thereby giving rise to a roll or operative gap which varies over its arcuate length~ Ihat is due to 45~)7 the fact that the mutually crossing ribs only ~o-operate along the generatrl oe s of the oe ntral roller and the counterpressure surface, which pass through the point of intersection of the ribs, and thus apply the necessary pressure to the blank.
In that oonnection, it is advantageous for the segments of the ccunterpressure surface to be arranged on carriages which are guuded displaceably radially with respect to the central roller and which are mKvable preferably independently of each other by means of a control drive. In that ~ay, it is possible to take account of wear of the ribs but also differences both in the dimensi~ns of the blank and also in the properties of the material thereof.
It may also be provided that the control drive o~ the carriages is oonnected to a ~easuring means fcr measuring the articles when in the finally deformed condition and displa oe s the carriages in dependence on the detected measurement data, thereby providing for automatic ad~ustment of the counterpressure surface. Thus, it may be provided that random samples of the articles produced are taken from the stream leaving the apparatus, measured in the measuring means and compared to a predetermined tolerance range ~0 and the carriages carrying the counterpressure surface are adjusted such that the produced articles lie in the middle of the tolerance range.
It is fully possible for one of the mutually crossing ribs to be disposed perpendicularly to the axis of the oe ntral roller, but in that case the central roller and the counterpressure surfa oe , besides the relative rotaxy movement, must also perfor~ a relative movement having a oomponent in the axial direction of the roller.
In order to avoid that additional movement which, in that case, can be controlled in any desired manner, and in order thereby to permit the apparatus to be simpler in construction, it may be provided, in acoordance ~ith a further feature of the invention, that ~LZ64S~7 each of the mutually crossinq ri~s of the central roller and the co-operating surface extend at an inclined angle with respect to the axis of the central rDller. That arrangement ensures that the ribs constantly intersect each other during the rota~y MOVement of the central roller, if we disregard an intake and discharge region of the apparatus, for the feed of blanks and the discharge of finished articles, which region is kept free of ribs.
In order to ensure precise entrainment and guidan oe of the blanks during processing thereof between the central roller and the caunterpressure surface, a further feature of the invention may provide that the central roller is drivingly connected by way of transmission means to an entrainment means for the blank, which entrainment means has at least one but preferably two rotary members which are spaced from each other in the axial direction cf the central roller and in which push rods or thrust members are held displaceably in the longitudinal direction thereof and engage by n~ans of a sliding memker or the like in a peripheral control groove which is disposed in a stationary part of the apparatus, wherein the thrust members which are guided in two different rotary memkers are axially aligned with each other. Those features provide that ~he blanks are clamped and thus entrained between the thrust m~aer and a cam , but better between a respective pair of mutually axially aligned thrust members. In that arrangement, it may further be provided that the control groove, with the exception of a feed and discharge region for the blanks and the finished bodies of revolution respectively, extends substantially parallel to the path of the points of intersection of the ribs of the central roller and the counterpressure surface during the rotary movement of the roller, wherein the c~ntrol grooves which are 30 associated with the thrust m~mbers guided in both rotary members 5~)7 extend parallel to each other in that region, thereky ensuring a precise guidance action for the blanks and easy feed of the blanks and removal of the finished bodies of revolution.
When producing ~odies of revolution with peripheral grooves, additional compacting or cGnsolidation in the region of the walls of the qroove may be desired in some cases. In such a situation, the control gro w e may be inclined with respect to the imaginary line ~hich is formed from the path of the points of intersection of the ribs of the central roller and the counterpressure surface. By virtue of that arrangement, the ribs press not only radially against the blank kNt also axially against the walls of the groDve which are being formed.
A preferred embodiment of an apparatus aco~rding to the invention further provides that at least the mutually facin~ end regions of the thrust memkers are rranged to be rotatable about the longitudinal axis of the thrust members, wherein preferably the end regions of the one thrust mem~ers are spring-loaded relative to the ccaxially aligned thrust members. That avoids friction between the end faces of the blanks and the thrust members. Ey virtue of the end regions of the one thrust members being resiliently suppDrted, that arrange~ent eliminates excessive pressure against the blank heing processed when the blank grGws in the axial direction due to the groove being impressed therein. In addition, that arrangernent also makes it possible to oompensate for dimensional variations in the blanks. The end regions of the thrust members may be formed by inserts.
In accordance with a further feature of the invention, it may also be pro~ided that provided for the entrainment means is a ring g~r or spur gear which is non-rotatably connected to the c~ntral roll~
and into whic~ engage gear transmissions drivingly conn~cted to 5~)7 support shafts disposed parallel to the thrust members, wherein the support shafts are held in the pressure members guiding the thrust members, or rotary member which are non-rotatably connected thereto.
Those features provide that the blanks are driven during the operation of processing same, while, by virtue of suitable matching of the gear transmissions, the peripheral speeds of the central roller and the blanks can be matched to each other.
Another purpose of the invention is to propose a method which is universally suitable for the production of differently shaped rotating bodies and in which the gradual use of pressure is possible.
According to the invention, this purpose is achieved in that two intersecting pressure zones are processed, the said pressure zones being moved in re-lation to each other and the blank being moved as a function of the line passing through the point of intersection during rela-tive movement of the pressure zones and of the changes in diameter to be produced.
As a result of the relative movement on the intersecting pressure zones and guidance of the blank, it is possible to produce therefrom rotating bodies of any desired configùration, and the period during which the pressure zones act upon the blank may also be ex-tended.
In the case of rotating bodies with peripheral grooves, it may be desirable for the blanks to be moved substantially in parallel with the pattern of the intersections of pressure zones arising during the re-lative movement thereof.
On the other hand, in producing rotating bodies having spiral grooves, for example threads, provision may be made for the blank to move at an angle, corresponding to the pitch angle of the spiral groove to be produced, to the line corresponding to the geometrical location of the intersection of the pressure zones during ~;~6~50~

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their relative movement, a blank having the outside diameter of the desired thread being used to produce the thread.
In the case of threads, especially trapezoidal threads or the like, the advantage of using blanks having the outside diameter of the thread is that material need not flow down the flanks of the threads in order -to build up the thread ribs completely which, under certain circumstances may lead to over stressing of the material and to the formation of cracks in the outer surfaces of the thread ribs; instead, the material can flow only axially, thus ensuring that the said thread ribs are made of solid material and cannot contain cavities or cracks covered by material expelled outwardly.
On the other hand, in order to produce rotating bodies having at least two sections of different diameters, it is desirable for the intersecting pressure zones to be at least sectionally narrower than the section of the rotating body to be produced and having a smaller diameter; moreover the blank is moved at an angle to the line corresponding to the geometrical location of the points of intersection of the pressure zones during the relative movement thereof.
Another purpose of the invention is to propose an apparatus for the implementation of the method.
In the case of an apparatus comprising a roller, and a counter pressure surface cooperating therewith, which are adapted to move in relation to each other, and in which at least one raised profiled rib is arranged on the said roller and on the said counter pressure surface, it is therefore proposed, according to another characteristic of the invention, that the profiled ribs be arranged to intersect each other, and that a guide for the blank be provided, the course of which is re-lated to the line determined by the points of inter-section of the ribs during rotation of the roller. This 45~7 is a simple way of ensuring intersecting pressure æones, it being possible to select the course of the guide for the blank, depending upon the rotating body to be pro-duced, in relation to the course of the points of intersection of the profiled ribs arising during rota-tion of the roller.
For the production of rotating bodies with peripheral grooves, provision may be made for the guide to run substantially parallel with the line deter-mined by the points of intersection of the profiled ribs during rotation of the roller, the counter pressure surface being preferably divided into segments displaceable radially of the roller. This ensures that, throughout the entire process, the profiled ribs always act sub-stantially in the same axial position upon the blank.
Minor deviations in parallelism between the guide and the points of intersection of the profiled ribs arising during rotation of the roller, may be provided in order to make allowance for the increase in the length of the blank being processed caused by the incorporation of a groove or by sectional reduction of the diameter, or in order to strengthen the walls of the ribs.
In the case of a counter pressure surface divided into segments, it is also possible, based upon intersecting profiled ribs, to locate the said counter pressure surface closer to or farther away from the roller. This is possible because intersecting profiled ribs can contact each other in extreme cases only along a surface line. In the case of known devices having parallel profiled ribs, however, this is not possible since, in the event of a change in the radial position of the counter pressure surface, a gap, varying over the length of the arc, would be produced between the cooperating surfaces of the profiled ribs.
On the other hand, in producing rotating bodies having spiral grooves, it is desirable for the guide to run at an angle, corresponding to the pitch of the groove to be produced, to the line determined by the "

X6~507 fo points of intersection of the profiled ribs during rotation of the roller. By means of the angle, corres-ponding to the pitch of the thread to be produced, between the course of the guide and the line arising during ro-tation of the roller and determined by the points of intersection of the profiled ribs, it is possible to form the thread in a very simple manner with profiled ribs corresponding to only one thread rib. In this connection it is, of course, necessary to make allowance for the increase in length of the blank caused by impression of the groove, if a blank having the outside diameter of the thread to be produced.
In producing rotating bodies having sections comprising at least two sections of different diameter, provision may be made for the guide to run at an angle to the line determined by the points on intersection of the profiled ribs during rotation of the roller, the difference, caused by this angle, in the distance between this line and the guide, along a path corres-ponding to one revolution of the blank, being less than the width of the profiled rib, and the difference in distance between the line determined by the points of intersection in the feed area for the blank and a removal area for the finished rotating body corres-ponding to the length of the smaller diameter section of the rotating body. This ensures that not only a pressure in the radial direction is applied to the blank during processing, but also a pressure in the axial direction, thus assisting the material to flow.
The intersecting profiled ribs make it possible also to produce bodies having a pointed or stream-lined end area. It is merely necessary to design the profiled ribs accordingly, the said ribs coming into contact with each other as -they rotate.
Moreover, according to a preferred example of embodiment of the invention, the segments of the counter pressure surface may be arranged in carriages ~2~5~17 ff displaceable radially in relation to the central roller, the said carriages being adapted to move, preferably independently of each other, by means of a control drive. This provides a simple way of compensating S for differences in blanks as regards their dimensions, hardness and strength. Provision may also be made to feed to the control drive signals from an automatic measuring device which checks the finished rotating bodies at random and measures them. This makes it possible to adjust the counter pres.sure surface in such a manner that the finished rotating body is within the central region of the tolerance range provided.
Accordin~ to another characteristic of the invention, each of the intersecting profiled ribs on the central roller and the counter pressure surface may run at an angle to the axis of the central roller.
It is quite possible to arrange one of the inter-secting profiled ribs at right angles to the axis of the central roller and to cause the counter pres-sure surface to carry out a relative movement in addition to the relative rotary motion, the said relative motion comprising a component running axially of the roller.
This additional movement is unnecessary if the profiled ribs on the roller and on the counter pressure surface are at an angle to the axis of rotation of the roller.
The invention also relates to an improved method for producing rotating bodies having at each end different diameters or axial sections with different diameters in which, when the blank is rotated about its axis, a pressure exceeding the yield point of the material of the blank is applied locally in order to reduce the diameter thereof. The invention also relates to an appara~us for the implementation of the said method.
In the case of existing known methods of this kind, a profiled rib arranged upon a roller was pressed into a blank supported by a counter pressure roller rotating in the opposite direction, the said profiled roller being at least as wide as the length of the section of the section of the blank whose diame-ter is to be reduced. In practice, this s1gnified that pressure is applied simul-taneously to the whole area whose diameter is to be reduced.
The disadvantage of this, however, is that very large forces and a large amount of power are required. Furthermore, with this known method it is very difficult to start the material flowing.
According to a further aspect of the invention, there is thus provided a method of producing a rotation body having different diameters along the length thereof, which comprises the steps of a) rotating a blank about the longitudinal axis thereof and working the rotating blank between two pressure zones to apply thereto a local pressure exceeding the flow limit of the- blank material whereby circularly extending impressions of different diameters are worked into the blank, the pressure zones crossing each other, b) displacing the pressure zones relative to each other while applying the local pressure, one of the pressure zones being displaced in a direction at an angle to its longitudinal extension and to the longitudinal direction of the pressure zone it crosses and the points of crossing of the crossing pressure zones forming a geometric line at an angle with the longitudinal axis of the blank to be worked, and c) displacing the blank in dependence on the geometric line and on the different diameters to be produced.
The present invention also provides, in another aspect thereof, an apparatus for producing a rotation body having different diameters along thc length thereof from a rotating blank, which comprises:

126~5C)7 a) a roll having at least one radially pro~ecting profiled rib, b) a counteracting pressure surface cooperating with the roll and remaining in a constant position relative to the roll in an axial direction, the pressure surface having at least one radially projecting profiled rib crossing the rib on the roll, c) means for rotating the roll abo~t the longitudinal axis thereof relative to the counteract-ing pressure surface whereby the displacement motion between the roll and the counteracting pressure surface has a component extending circumferentially about the roll and the points of crossing of the crossing ribs form a geometric line at an angle with the longitudinal axis, and d) guide means for displacing the blank relative to the geometric line in the axial direction in dependence on the differen-t diame-ters to be produced while the blank is rotated and subjected to pressure exceeding the flow limit of the blank material between the roll and the pressure surface.
According to still a further aspect of the invention, there is provided an apparatus for producing a rotation body having different diameters along the axial length thereof from a rota-ting blank, which comprises:
a) a roll having a longitudinal axis, b) a counteracting pressure surface cooperating with the roll, the pressure surface and the roll having a radially projecting profiled rib, the profiled ribs being inclined with respect to the longitudinal axis of the roll and crossing each other, c) means for ratating the roll about the longitudinal axis thereof and applying to the rotating blank between the roll and the pressure surface a local pressure exceeding the flow limit of the blank material to reduce the diameter of the 5~7 blank along an axial sec-tion thereof by displacing, each rib in a dlrection parallel to the longitudinal axis, each rib having a smaller dimension in the axial direction of the blank tildrl the reduced diameter blank section whereby the displacement motion between the roll and counteracting pressure surface has a componen-t extending circumferentially about the roll and the points of crossing of the crossing ribs form a geometric line, and d) guide means for displacing the blank inclined with respect to the geometric line.

- 13a -~Z~507 In producing ro-tating bodies with peripheral grooves, additional compacting in the vicinity of the walls of the grooves may be required in many cases.
In such a case, the control groove may be at an angle to -the imaginary line arising from the course of the points of intersection of the profiled ribs on the central roller and the counter pressure surface. In this case the profiled applied pressure to the blank not only radially, but also axially to the incipient walls of the grooves.
In this connection, and according to another characteristic of the invention, provision may be made for the profiled rib(s) on the central roller, and those arranged on the counter pressure surface, preferably divided into a plurality of segments ad-justable radially in relation to the roller, to run at an angle to the axis of rotation of the roller, and to intersect in the course of their mutual re-lative motion, a guide being provided for the blank, the said guide running at an angle to the line deter-mined by the points of intersection, arising during rotation of the roller, of the edges, corresponding to each of the profiled ribs, the difference, caused by this angle, in the distance between this line and the guide, along a path corresponding to one revolution of the blank, being less than the width of the profiled rib and the difference in the distance between the guide and the line determined by the points of inter-section in the feed area for the blank and the removal area for the finished rotating body corresponding to the length of the smaller diameter section of the rotating body. This ensures that, as compared with the grooves or sections to be produced, the narrow profiled ribs with reduced diameter are ~oved axially over the blank, although this does not result in the forming of spiral grooves. This axial movement, how-ever, causes a pressure to be applied through the 12~45~7 flanks of the profiled ribs, in the axial direction, to the walls of the groove to be produced, or to the shoulder of the section, with reduced diameter, to be produced, and this leads to compacting of the ma-terial in this area.
The invention will now be described in greater detail with reference to the drawings in which:
Figures lA and lB diagrammatically show tools for carrying out the method according to the invention and deformation of a blank using such tools, Figure 2 shows the development of the shaped ribs of the tools shown in Figures lA and lB, Figure 3 is a view in vertical section of an embodiment of an apparatus for carrying out the method according to the invention, Figure 4 is a plan view of the apparatus shown in Figure 3, Figure 5 is a detail of the apparatus shown in Figures 3 and 4 on a larger scale, Figure 6 is a detail of the thrust member guide arrangement of the apparatus shown in Figures 3 and 4, on an enlarged scale, Figure 7 shows a further detail of the thrust members, Fi.gure 8 is an exploded view of the entrainment means of the apparatus shown in Figures 3 and 4, Figure 9 is a front view of the entrainment means, and Figure 10 is a plan view of the entrainment means.
Figure lA is a diagrammatic view of the shaped ribs 7 and 8 which are disposed on the counter-pressure surface 1 which is subdivided into five seg-ements 2, 3, 4, 5 and 6. The rib 7 serves to form the step or shoulder 10 of the finished article 9v produced from the blank 9. On the other hand, the rib 8 serves to form out the groove 4~5~7 ~p 11 of the finished article and has its maximum width and minimum height at the beginning of the counter pressure surface or at the boundary of the intake region for the blanks 9 which are to be handled. Along its path from the beginning of the rib 8 to the end thereof at the edge of the segment 6 which, as will be described hereinafter, is the trailing edge as considered in the direction of rotation of a central roller, the width of the rib 8 progressively decreases and it terminates in a form which is equal and opposite to the groove 11.
Profiled rib 7, which forms shoulder 10 in the finished rotating body, increases in width and height on the way from cross-section x, at the edge of the input area, to cross-section x5 at the run out edge of segment 6 and the beginning of the discharge area for the finished rotating body 9V.
The central roller 12 shown in Figure lB
runs in the space enclosed by the segments 2 to 6 of the counterpressure surface, but was not shown jointly therewith, for the sake of enc'hanced clarity of the drawings. The roller 12 is installed in such a way that, in-a position of the roller 12 relative to the segmen-ts 2 to 6 of the counter pressure sur-Eace 1 in which the beginnings of the ribs 7' and 8' are radially aligned with the beginnings of the ribs 7 and 8, they are also at the same height.
The cooperation between the two groups of profiled ribs 7, 8 and 7', 8' is best seen from Fig. 2 which shows the development of profiled ribs 7, 8 on counter pressure surface 1 and of profiled ribs 7', 8' on roller 12. Profiled ribs 7, 8 ascend from left to right, while profiled ribs 7', 8' descend from left to right. As roller 12 rotates in the dir-ection of arrow 13 in Figure lB, profiled ribs 7', 8' will be moved in the direction of arrow 13 in Figure 2 in relation to profiled ribs 7, 8.

~;~6~507 ~ .;;i' As may be gathered from Figures lB and 2, the cross-sectional shapes of profiled ribs 7', 8' varies in the same way as that of profiled ribs 7, 8, i.e. profiled xib 7' widens from cross-section x to cross-section x5, while profiled rib 8' increases in width, in the vicinity of its maximal elevation, and in height.
As a result of the arrangement of the profiled ribs on counter pressure surface 1 and roller 23 opposed 1~ to each other and at an angle to roller 12, rotation of the said roller produces continuously points of intersection of these ribs. These produce an imaginary line substantially parallel with dotted line 15 which corresponds to the geometrical location of the points of intersection of profiled ribs 8, 8' arising when roller 12 rotates. As may be gathered from Figure 2, blanks 9 are guided in parallel with line 15 between two tappets 14, 1~', line 15 being at a slight angle to profiled rib 8, in order to make allowance for the increase in the length of the blank when the groove is impressed therein.
Since the edge of profiled rib 7 or 7' closer to line 15 form an angle therewith, blank 9, on its way from cross-section x to cross-section x5, is subjected, between roller 12 and counter pressure surface 1, not only to a radial pressure, not only because of the increasing height of the profiled ribs along this path, but also to an axial pressure applied to shoulder being formed. This pressure promotes and facilitates, to a considerable extent, the flow of material, especially in the axial direction. The change in the shape of blank 9, upon reaching individual cross-sections x to x5, is shown in Figure lA.
The change in the cross-sectional form of rib 8 from segment to segment or from segment boundary to segment boundary can be clearly seen from the change in the configuration of the blank 9, to give the finished /~

article. I'hus, the intermediate product 9' corresponds to the condition of deformation of the blank 9, as occurs at the boundary xl between the segment 2 and the segment 3. That shows the cross-sectional form of the ribs in that cross-section. In the same fashion, the intermediate product 9" corresponds to the condition of deformation of the blank in the cross-section x2, the intermediate product 9''' corresponds to the con-dition of deformation of the blank at the cross-section x3 and the intermediate product giV corresponds to the condition of deformation at the cross-section x4. In the cross-section x5, the blank is formed to give the finished body of revolution 9V, It will be clearly seen from the form of the intenmediate products 9~, 9,,, 9" " giv~ gv, that ths rib 8 and the rik~ 8' ~Figure lb), fxom their begLnning, decrease in respect of their width at their location of yreatest height, in their respective cross-S secti~n, whereas the ribs 7 and 7' increase in width.
It will also be seen fro~ Figure.LA that during processing theblanks 9 are held between two thrust members or pushrods 14 and 14' which separate fro~ each other in the intake and discharge re~ion which is between the cross-sections 5x and x, and thus ~0 enable the blanks 9 t~ be intxoduced and the finished articles to be rem~ved, such operations occurrin~ in different planes.
~ igure lB diagrammatically shows the central roller 12 which.
oo-operates with the counterpressure surface 1. The roller 12 is proYided with two shaped ribs 7' and 8' which correspond to the ribs 7 and 8 but which are inclined in the opposite direction _ to the ribs 7 and 8 so that when the central roller 12 is fitted between the segments 2 to 6, the ribs 7, 7' and 8, 8' respectively cross each other when the central roller 12 rotates in the direction indicated by the arr~w 13.
AS can be seen fron ~iyure 2 which shows a developT~nt of the ribs 7, B, 7' and 8', the ribs 7' and ~' are m~ved past the ribs 7 and 8 in the direction indicated by the arrow 13, whereby the points of intersection of the ribs move incl~edly dow~w~rdly towards the r~ght. In that arranyement, the ~lank 9 is guided bv the two thrust n~bers 14 an~ 14' substantially along the line which corresponds to the geometrical locus of the points of intersection o~ the ribs 8 an~ 8' during ~he relative mov~ment of the ribs 7 and 8 with respe~t to the ribs 7' and 8'~
~he thrust m~mb~rs 14 and 14' are guided between the bour~laries .
x and x5 of the segments of the surface 1 along the imaginary b2se ... .

~26~07 lines 15 and 15' which are shown in dash-dotted fo~m and which extend parallel to the ribs 8 and 8'. The lines 15 and 15' are slightly inclined with respect to the line corresponding to the geometrical locus of the points of intersection, thereby taking account oE the axial growth in length of the blank 9 due to the groove 11 being impressed therein.
It will be appreciated that the blanks 9 are not guided along two different paths, but the dash-dotted lines 15 only indicate the path of the blanks with respect to the ribs 7, 8 and 7' and 8' respectively. In practice, as will be described in greater detail hereinafter, the blanks are in principle controlled by a groove which is provided in a stationary part of the machine and the configuration of which substantially corresponds to that of the rib 8.
With the above-described arrangement, as considered from the central roller 12, the path of movement of the blanks is parallel to the rib 8'.
As may be gathered from Figures lA to 2, especially from Figure 2, with profiled ribs of the same design it is possible, merely by altering the angle, at which the blank is guided during processing, to the line produced during rotation of -the roller and determined by the points of intersection of the profiled ribs, to change the shaping of the blank.
Thus profiled ribs 8, 8' with a guide inclined according to them, e.g. corresponding to dotted line 17 in Figure 2, could also be used to produce a spiral groove, and the angle between profiled ribs 8, 8' and the path of the blank would determine the pitch of such a spiral groove. The only requirement would be that profiled ribs 8, 8' be narrower than the lead of the groove on the rotating body to be produced. If this is not so, arranging the guide at an angle to profiled rib 7', 8' will produce a peripheral groove, the width thereof exceeding that of profiled rib 8, 8'. The pressure applied axially to the blank by profiled , .

~;~6~SO~

rib 8, 8' would produce cornpacting of the material in the vicinity of one wall of the groove.
If the angle between profiled rib 8, 8' and the path along which blank 9 is guided between roller 12 and the counter pressure surface is large enough, profiled rib 8, 8' may also be used to form a section of rotating body gv having a smaller dia-meter. This merely requires that the blanks be guided along a path which leads upwardly in relation to pro-filed rib 8, 8', for example along dotted line 16 shown in Figure 2.
This would cause the pressure zones determined by profiled ribs 8, 8' to shift axially in relation to the blank, whereas in the case of pressure zones determined by profiled ribs 7, 7' and guidance of the blank according to line 15 in Figure 2, only a restriction of the pressure zones in the axial direction in relat.ion to the blank is moved.
As can be seen from Figures lB and 2, the cross-sectional shape of the ribs 7' and 8' also alters in the same ashion as that of the ri.bs 7' and 8', that is to say, the rib 8' increases in height from its beginning to its end and decreases in width in the region of its maximum height.
Figure 3 is a diagrammatic view of an ap-paratus for carrying out the method according to the invention, in vertial section, in which in particular the mounting and bearing means and the installation thereof are shown in simplified form. In addition, structural groups and units which, for manufacturing reasons and for reasons of greater ease of assembly, consis-t of a number of parts, are shown in part as being formed as one part.
The drive motor 20 drives a shaft 23 by way of a clutch 21 of which one half is connected to a flywheel 22. The shaft 23 is 5~)7 ~/

supported in the housing 26 in ccnventional manner by way of the rolling bearings 24 and 25 and is non-r~tatably connected to a bevel gear 27 and a chain wheel 29~
m e bevel gear 2~ meshes with a further bevel gear 28 which is non-rot.atably oDnnected to a vertically disposed main shaft 3~.
m e main shaft 30 is held by means oi ~wo tapered roller kearings 31 and 32 in a carrier cylinder 33 connected to the housing 26.
A first guide member 34 is fitted on the cylinder 33 and is rigidly connected thereto. In addition, disposed on the cylin~er 33 is a needle bearing 35 which is axially fixed in position by the guide member 34 and a support flange 36~ and which rotatably mounts a rotary member 37 provided with a chain ring 38. The rotary member 37 or the chain ring 38 thereof is connected by way of two chains 39 to chain wheels 40 which are non-rotatably connected to the output shaft 41 of a transmission 42. ~e transmission 42 is driven by way of two chains 44 and chain wheels 43 by the shaft 23 or the chain wheels 29 connected thereto, and is held in the housing 26' by way of a bracket 46.
The rotary ~ember 37 is connected by way of pins 45 to a further rotary ~ember 47 and is mcunted to the main shaft 30 by way of a rol1ing bearing 48. The two rotary members 37 and 47 are also connected together by way of slotted guide sleeves 49 in which the thrust memkers 14' or the guide heads 50 thereof are axlally slidably guided. The guide heads 50 engage with their rotatably mounted roller 51 into a oontrol groove in the guide n~ber 43.
The thrust memkers 14' pass through the rotary ~ r 47 and are guided therein in bushes 53. In addition, secured to the rotary mem~er 47 is a splash ring 54 which serves to car~y the oil used for lubrication purposes away into an annularly disposed oil sump (not shcwn).

5~7 ,., m e rotary n~ er 47 is connected to a further rotary n~ber 56 by way of struts 55. Llke the rotary member 47, the rotary member 56 is provided with tangentially extending portions of dcvetail guides which serve to acco~cdate sliding members which are parts of the entrainment means shown in Fiyures 8 to 10 and are descri~ed hereinafter with reference to those ~igures. For the sake of enhanced clarity of the drawing, ~he correspondiny reference numerals are not shown in Figure 3.
. N~n-rotatably disposed on the main shaft 30 is a chuck body 57 on to which is fitted the roller 12 which ~ears the ribs 7~ and 8'1 being held in position non-ro~atably by means of a key and gro~ve connection. Screwed to the roller 12 is a ring gear or spur gear 58 from which the drive for the entrainment means is derived, as will be described in greater detail hereinafter with reference to Fi~ures 8 and 10.
A sleeve 59 is fitted on a stepped portion of the main shaft 30 and non-rotatably connected thereto by way of a key and groove D tion. Mkunted on the sleeve 59 by way of a rolling bearing 60 is a rotary n~ er 62 which is screwed to an internal ring gear 61. P~s can be seen from Figure 5, the ring gear 61 meshes with interm~diate gears 63 which in turn mesh with further gears 64 which serve only to xeverse the direction of rotation and which, like the intermediate gears 63, are mounted rotatably in a ring 66 disposed in the in~erior of a further ~uide memker 65 which is fixed with respec* to the housing. m e gears 64 in turn mesh with a ring gear which is dis~osed on the sleeve 59 and which provides for the drive for the rotary member 62 by way of the gears 63 and 64 and the ring gear 61 which supports the guide n~ er by way of a rolling bearing 60'.
The rotary member 6~ is connected by ~ay of pins 67 and a sleeve 68 to a ring 69 in which are mounted bushes 53 in which the thrust ~6~5~7 members lg are rotatably and axially displaceably guided, just as in the r~tary n~ er 62.
The guide member 65 is of a two-part construction and supports the main shaft 30 by way of a rolling bearing 69'~ In addition, the guide member 65 is provided with a oontrol groove 70 into which engages a rotatable roll~r 51 carried in each guide head 71 of the thrust members 14, as shown on a larger scale in Figure 6. As shown in Figure 6, the pin 72 carrying the roller 51 engages with an extension portion into a peripheral groove 73 in the thrust member 14 whereby the latter is mounted rotatably but axially displaceably in the guide head 71.
Over the major part of the periphery of the guide member 65, the oDntrol groove 70 extends parallel to the control groove 52 of the guide ~ember 34. It is only in the intake and discharge regi~n which was described with reference to Figure lA that the above-indicated parallel condition does not occur and in that region the two control grooves move apart and ~ack towards each other again.
~he guide member 65 can be connected ~y way of a flanged member 74 to a support arm 75 in which the main shaft 30 is supported in a plain bearing. The support aLm 75 is supported on a carrier pillar 76 which is fixed on the housing 26'. Disposed in the pillar 76 is a spindle 77 which is supported relative to the inside wall surface of the pillar 76 and relative to a cylinlrical b~re 79 ~5 of the support arm 75 by means of a centering ring 78 in its upper region. The support arm 75 is clamped to the pillar 76 by means of a nut 80.
After unscrewing and removing the nut 80 and releasing the connection between the flanged member 74 and tbe support arm 75, the latter can be lift~d and pivoted whereby it is possible to 5(~

dism~ntle ~he apparatus, in crder for example to replace the roller 12 by another roller with ribs of a different canfiguration in order to be able to produ oe different bodies ~f revolution.
Also arranged on the housing 26'are five carriages 81 which carry the segments 2 to 6 of the oO-Dperating surfa oe 1. The carriages Bl are guided in housings 82 in each of which is disposed a screw-~hreaded spindle 84 supported in a bear m g arrangement 83 eomprisin~
thrust and radial rolling be~rings. Ihe spindle 84 is driven by a stepping motor 86 by way of a transmision 85 and it passes through two nuts 87 which are braced relative to each other to o sate for play at the spindle, which in turn is connected to the carriage or slide body 88 which is quided in the housing 82 and which incorporates a weak location 89 for carrying wire strain gauges.
~ounted at the end of the body 88 is an ~djustable-height ~ ~ support, which, tcqether with the adjustinq spindle associated there-with, is generally denoted by reference nu~eral 90. Secured to the support 90 is a seqment of the co-operating surface 1 which bears the ribs 7 and 8.
A peripheral cam 92 is unted to the carriages 81 and the pillar 76 by way of mounting arms 91. As will be described in greater detail hereinafter with reference to Figures 8 and 9, the cam 92 is provided for controlling the entrainment means.
m e feed means for the blanks to be worked upon, which can be better seen from Figure 4, is indicated generally by reference numeral 93 and is driven by the transmission 42 by way of a chain wheel 94 and a chain g5.
The step-up ratio of the transmission 42 and the chain wheels 40 and 38 as well as ~hat of the transmission f~rmed by the ring gear 61 and ~he ring gear of the sleeve 59 and the gears 63 and %~ ~ 507 64 is such that ~he rotaLy members wh~ch are driven by those transmissions, cn the path of mcvement described ky the thrust memkers 14 and 14' which are mounted m the rotary mimbers, move at half the peripheral speed of the peripheral surface of the roller bearing the ri~s.
In the carriage 81 shown in sect.ion in Figure 4, a vibration generator 96 is screwed into the segment of the oounterpressure surface 1 and causes ~he counterpressure surface to be displaced with high-frequency vibrations or oscillati~ns, thereby facilitating deformation of the blanks 9 which are guided between the seoments of the surface 1 and the roller 12 ky means of an entrainment arrangement which is not shcwn in Figure 4 for the sake of enhan oed clarity of the drawing.
As can be seen from Figure 4, the supply means 93 has an inclinedly extend m g channel 97 which guides the blanks ~ into the star wheel 98~ The star wheel 98 transports the blanks to a fur~her star wheel ~9, while for the purposes of transferring the blanks the a~rangement includes a guide plate 100 which is secured to the housing 26' by way of a hold OE which is not shown for the sake of enhanced clarity of the drawings.
Punches 101 of which only two are illustrated are guided in the star wheel 99 which rotates in a plane which is displaced with respect to the star wheel 98~ The punches 101 project beyond the upper fa oe of the star wheel 99 and slide against the cam 102.
The cam 102 which is stationary causes the blanks to be pushed out into the path of thie thrust mRmbers 14 and 14' ~y which they are engaged or clamped.
Disposed in ahorizontal plane which is different fr~m that of the feed means is a magnet 103 which, after the finished bodies of revolution gv are released by the thrust m~mbers 14 and 14', conducts them into a further channel 104.

~4SOt7 Inoorporated into the channel 104 is a switching means 105 which pe~mlts a body of revolution to be selectively removed from the channel by a deflection plate 106 being inserted thereinto by means of the piston-cylinder arrangemen ~ m e ~ody of revolution which is remKved from the ch~nnel in that way then passes ~y way of a chan~el lOB to a measuring device 109 in which the body of revolution is pushed by means of a piston 110 into a measuring position in which it bears against an abutment 111 which is pivotable by n~ns of a piston-cylinder arrangement 112. The ~easuring operation itself is carried out by means of an optical measuring head 113 which pxoduces the measuring result in the form of electrical signals which are passed to a control means (not shown) for example a process computer. In the case where the measurement values obtained are tcwards the limits of a predetermined tolerance range, the control means passes suitable control instructions to the stepping tors 86 of the carriages 81, to provide for suitable adjustn~nt thereof.
That makes it possible to observe very close toleran oe s.
After the operation of measuring the body of revolution, the abutment 111 is pivoted by the piston-cylinder arrangement 112 and the piston-cylinder arrangement 110 pushes the body of revolution which has already been measured to the openlng 114 through which it slips to the exterior by way of the channel 115.
Figure 7 shGws the end regions of the members 14 and 14' on an enl~rged scale, said end regions beiny rotatable about the l~ngitudinal axis of the n~bers 14 and 14'. In that arrangement, screwed into the thrust member 14 in the end thereof is an insert 116 in which a tip 117 is held by means of a pin 119 which passes thr~ugh a transverse 118 in the tip 117 and which also passes through the walls of the insert 116. The tip 117 is axially displaceably held in the insert 116 and is subjected to th~ for oe ~ ~L~?~ 5 O 7 of a spring 120. As the transverse ~ore 118 is larger in diameter than the tip, this arrange~ent provides for a slight amount of axial displacement of the tip 117 relative to the insert or the casing thereof. That makes it possible to ccmFensate for slight S dimensional variations in the blanks 9 and to compensate for the growth in length of the blanks while they are being deformed by the ribs 7, 8 and 7', 8' respectively of the counterpressure surface 1 and the roller 12.
A sleeve 121 is screwed on to the screwthreaded spigot 120 of the thrust memker 14'. A slide bush 122 is fitted into the sleeve 121 and secured therein with an inse~t mimber 123. A tip 124 is rotatably carried in the bush 122, the collar on the tip being supported against a slide ring 125 which in turn is supported against a shoulder of the sleeve 121.
~he arrangement of the rotatable tip 12~ of the thrust mem~ers 14' and the r~tatable unting of the thrust members 14 in the guide heads 71 thereof ensures that friction between the thrust members 14, 14' and the blanks 9 which are held therebetween is elimlnated.
The entrainme~t means will be described in greater detail with reference to Figures 8, 9 and 10.
m e rotary members 47 and 56 are provided in a section-wise manner with tangentially extending, radially projecting dovetail guides 126. Two slide members 127 are displaceably disposed on each of the sections of the dovetail guides. Ihe thrust members 14 and 14' pass be~ween the projections on the r~tary n~nbers whereas the support rollers l?B are rotatably mounted in the bores 129 of the slide n~ ers 1~7. m e slide ~embers ~27 which are mounted in different rotary members 47 and 56 respectively are connected together by way of the pressure members 130 which 3L;~6~5~

~CI

are screwed to the s~de n~s~ers 127.
The members 130 are controlled ky respective cam shafts 131 whose cylindrical projections 132 extend thrcugh and are rotatably mcunted in the ~ores 133 disposed in the radially proj~cting S porticns of the rotary nY~ers 47 and 56. The upper cylindrical projections 132 are each non-rotatably clamped in a respectiv~
control lever 134 while the projections 132 ~ngage into the bores 135 which define a slot 136. m e control levers 134 slide alony the stationary cam 92 upon rotary mavement of the two rotary members 47 and 56.
Over the arcuate region over which the counterpressure surface 1 extends, the cam 92 describes substantially a circular arc. In the reyion of the feed and discharge area for the blanks ~ and the finished bodies of revoluti~n respectively, the cam 92 has a depression 137 which permits-pivotal--mcvement of the control levers.
The support rollers 128 have a region which is provided with knurling and which comes into contact with and drives the blanks 9. The support rollers are driven ky the gears 138 which are non-rotatably connected to the support rollers. The g OE s 138 mesh with intermediate gears 139 which are rotatably mounted with a respective gear 138 in a holder 14~, the intermediate gears 139 meshing wnth the gear 58 oonnected to the roller 12 carrying the ribs 7' and 8'. In that arrangement, because of the diff-erence in speed between the gear 58 and the holders 140 which are also moved by virtue of the driving connection to the rotary ~embers 47 and 56 which is prcvided by the support shafts 128, a rolling mKvement of the intermediate gears 139 is produced and thus the suFport shafts are driven.
As can be seen from Figures 9 and 10, the respectively ~69~507 ~g , assoclated holders 140 are connec,~ed together by a pin 141, with the t~o holders 140 being braced tcwards each other by two springs 142.
As long as the co~trol levers 134 slide along the arcuate region S ~f the cam 94, they are deflected and the cam shafts 131 which are non-rotatably oonnec,ted thereto urge the mem~ers 130 and the support shafts 128 which are held therewith in the slide n~ ers 127 against the thrust memkers 14 and 14' and thus against the blanks 9 to be deformed. ~hen that happens, the holders 140 are urged apart against the force of the sprin~s 142. When one of the control lever~ 134 slides into the depression in the cam, that control lever can be deflected and the springs 142 can urge the support shafts 128 away from the thrust members whereby, by way of the pivotal movement of the cam shaft 131, the control lever 134 is alsD caused to pivot, being beld_in contact with the cam 92 by the springs 1~2.
As can be seen fro~ Figure 10, the intermediate gears 39 rotate in two different horizontal planes and are rotatably fixed on axle journals which are held at one end in thP respective holders 140. The step-up ratio of the transmissions 58, 139, 138 and the support shaft 128 or the diameter of the knurled region ~hereof are matched to each other in such a way that the peripheral speed of the knurled region of the support shafts 128 and thus also that of the blanks 9 ~earing thereagainst is equal to the peripheral speed of the periphery of the roller 12 carrying the ribs~ Although the blanks 9 are caused to rotate solely by the rolling ~ vement against the stationary co-operating surfaoe 1 and the peripheral surfa oe of the roller 12, as indicated by the arrows in Figure 10, nonetheless a certain sliding mavement of the blank against such surfaces may also occur during w~rking of '12~S~7 the blank. Ihat is prevented by the additional drive for the blanks by the support shafts, while, as can be seen from Figure 10, the blank 9 is always supported a~d driven between the support shafts 1~8 which are mounted in adjacent pairs of holders 140.
As can be seen from Figure 8, the pressure ~embers 130 have a groove ~hich is towards the supp~rt shafts 128 and which ext~nds in the axial direction and in which are disposed rolling memkers 14~ which project beyond the outer edges of the groove 145.
That substantially elimunates friction between the support sh2fts and the pressure n~s~ers 130.
When the control levers 134 go from the arcuate region of the cam 92 into the depression 137 therein, the intenmediate gears 13~ also perform an additional movement relative to the gear 58, by virtue of the tw~ holders 140 connected by the pin 141 moving towards each other, due to the springs 142. Although that .
additional movement results in a change in ~he speed of rotation of the support shafts, that is however of n~ importance as in that situation the support shafts 128 are moved away from the blank 9.
The ccntrol grooves 52 and 70 which detenmine the path of the hlanks 9 extend as indicated by the line 15 in Figure lA or parallel thereto, in the region covered ky the co-operating surface 1.
Outside that region, the paths of the control grooves have deviatio~s in opposite directions, the control grooves 52 and 70 moving further apart from each other and moving towards each other again so that in that region there is no clamping in respect of the blanks 9 or the ~odies of revolution 9 and the blanks ~an ~e introduced and the finished bodies of revolution can be removed.
In the illustrated em~xxlunent, the co-operating surface 1 is of ~i45(~7 a curved ccnfiguratlon corresponding to the roller 12, ~ut that is in no way ab~olutely necessary. Thus, it is also possible to use a flat ccunterpressure su* ace over which the r~ller mcves, in which respect it is irrele~ant whether the counterpressure surface is moved with respect to the axis of the roller or whether the roller is ~oved in parallel relationship with the oounterpressure surfa oe .

Claims (22)

1. A method of producing a rotation body having different diameters along the length thereof, which comprises the steps of a) rotating a blank about the longitudinal axis thereof and working the rotating blank between two pressure zones to apply thereto a local pressure exceeding the flow limit of the blank material whereby circularly extending impressions of different diameters are worked into the blank, the pressure zones crossing each other, b) displacing the pressure zones relative to each other while applying the local pressure, one of the pressure zones being displaced in a direction at an angle to its longitudinal extension and to the longitudinal direction of the pressure zone it crosses and the points of crossing of the crossing pressure zones forming a geometric line at an angle with the longitudinal axis of the blank to be worked, and c) displacing the blank in dependence on said geometric line and on the differerent diameters to be produced.

2. The method of claim 1, wherein the blanks are displaced substantially parallel to said geometric line whereby parallel circumferential grooves are worked into the blank.

3. The method of claim 1, wherein the blanks are displaced at an angle to said line to work a spirally extending groove into the blank, the angle of displacement corresponding to the desired pitch of the spirally extending groove and the pitch exceeding the width of the pressure zones.

4. The method of claim 3, wherein the spirally extending groove forms a screw thread and the blank has a diameter corresponding to the outer diameter of the screw.

5. The method of claim 1 for producing a rotation body having at least two circularly extending impressions of different diameters, wherein the crossing pressure zones have at least sections narrower than the circularly extending impression of smaller diameter, and the blanks are displaced along lines inclined with respect to said geometric line, the width of the pressure zones exceeding the difference between the inclinations of said inclined lines during one rotation of the blank.

6. The method of claim 1, wherein the crossing pressure zones are displaced in a direction having a component running parallel to the longitudi-nal axis of the blank to reduce the diameter of the blank along an axial section thereof, the pressure zones having a smaller dimension in the axial direction of the blank than the reduced diameter blank section.

7. The method of claim 1, wherein one of the pressure zones is fixedly arranged and the other one, crossing the first one is moved during applying a pressure at the blank to be worked in a direction at an angle to its longitudinal extension and to the longitudinal direction of the fixedly arranged pressure zone.

8. An apparatus for producing a rotation body having different diameters along the length thereof from a rotating blank, which comprises:
a) a roll having at least one radially projecting profiled rib, b) a counteracting pressure surface cooperating with the roll and remaining in a constant position relative to the roll in an axial direction, the pressure surface having at least one radially projecting profiled rib crossing the rib on the roll, c) means for rotating the roll about the longitudinal axis thereof relative to the counterac-ting pressure surface whereby the displacement motion between the roll and the counteracting pressure surface has a component extending circumferentially about the roll and the points of crossing of the crossing ribs form a geometric line at an angle with the longitudinal axis, and d) guide means for displacing the blank relative to said line in the axial direction in dependence on the different diameters to be produced while the blank is rotated and subjected to pressure exceeding the flow limit of the blank material between the roll and the pressure surface.

9. The apparatus of claim 8, wherein the guide means extends substantially parallel to said line whereby parallel circumferential grooves are worked into the blank.

10. The apparatus of claim 8, wherein the guide means extends at an angle to said line to work a spirally extending groove into the blank, the angle corresponding to the desired pitch of the spirally extending groove.

11. The apparatus of claim 8, for fabricating a rotation body having a circularly extending zone of reduced diameter, wherein the guide means extends in a direction inclined with respect to said geometric line whereby there is a difference in the distance between the guide means and the geometric line at the beginning and at the end of one rotation of the blank, as measured in the direction of the longitudi-nal axis, said distance being smaller than the width of the profiled ribs and the difference in said distances at a feeding zone of the blank to the cooperating roll and counteracting pressure zone and at a discharge zone of the fabricated rotation body corresponding to the length of the zone of reduced diameter of the rotation body.

12. The apparatus of claim 8, wherein each one of the crossing profiled ribs is inclined with respect to the longitudinal axis of the roll.

13. An apparatus for producing a rotation body having different diameters along the length thereof from a rotating blank, which comprises:
a) a roll having at least one radially projecting profiled rib, b) a counteracting pressure surface comprised of segments radially displaceable relative to the roll, the counteracting pressure surface cooperating with the roll and remaining in a constant position relative thereto in an axial direction, the pressure surface having at least one radially projecting profiled rib crossing the rib on the roll, c) means for rotating the roll about the longitudinal axis thereof relative to the counterac-ting pressure surface whereby the displacement motion between the roll and the counteracting pressure surface has a component extending circumferentially about the roll and the points of crossing of the crossing ribs form a geometric line at an angle with the longitudinal axis, d) guide means for displacing the blank relative to said geometric line in the axial direction in dependence on the different diameters to be produced while the blank is rotated and subjected to pressure exceeding the flow limit of the blank material between the roll and pressure surface, the guide means extending substantially parallel to said geometric line whereby parallel circumferential grooves are worked into the blank.

14. The apparatus of claim 13, further comprising carriages radially slidable relative to the roll and carrying the counteracting pressure surface segments, and control drive means for independently sliding the carriages.

15. An apparatus for producing a rotation body having different diameters along the axial length thereof from a rotating blank, which comprises:
a) a roll having a longitudinal axis, b) a counteracting pressure surface cooperating with the roll, the pressure surface and the roll having a radially projecting profiled rib, the profiled ribs being inclined with respect to the longitudinal axis of the roll and crossing each other, c) means for rotating the roll about the longitudinal axis thereof and applying to the rotating blank between the roll and the pressure surface a local pressure exceeding the flow limit of the blank material to reduce the diameter of the blank along an axial section thereof by displacing, each rib in a direction parallel to the longitudinal axis, each rib having a smaller dimension in the axial direction of the blank than the reduced diameter blank section whereby the displacement motion between the roll and counteracting pressure surface has a component extending circumferentially about the roll and the points of crossing of the crossing ribs form a geometric line, and d) guide means for displacing the blank inclined with respect to said line.

16. The apparatus of claim 15, wherein the roll is arranged centrally with respect to the cooperating counteracting pressure surface, and the inclination of the guide means with respect to said geometric line causing a difference in the distance between the guide means and the geometric line at the beginning and at the end of one rotation of the blank, as measured in the direction of the longitudinal axis, said distance being smaller than the width of the profiled ribs and the difference in said distances at a feeding zone of the blank to the cooperating roll and counteracting pressure zone and at a discharge zone of the fabricated rotation body corresponding to the length of the zone of reduced diameter of the rotation body.

17. The apparatus of claim 16, wherein the counteracting pressure surface is comprised of segments radially displaceable relative to the roll.

18. The apparatus of claim 15, wherein the guide means for displacing the blank comprises an entrainment device including two axially spaced rotary bodies, a respective tappet displaceable in a longitudinal direction thereof in a respective one of the rotary bodies, a respective fixed circumferential control groove receiving a sliding block means connected to the respective tappet, the tappets being axially aligned and extending substantially parallel to the longitudinal axis of the roll, and the blank being capable of being capable of being clamped between the tappets.

19. The apparatus of claim 18, wherein at least the facing ends of the aligned tappets are rotatable about the axes thereof.

20. The apparatus of claim 18, wherein the end of one of the aligned tappets facing the end of the other tappet is coaxially biased towards the same.

21. The apparatus of claim 18, wherein the entrainment device further comprises a toothed rim rigidly connected to the central roll for rotation therewith, gears in driving connection with the toothed rim, the gears being supported by shafts extending parallel to the tappets and the supporting shafts being held in the respective rotary bodies.

22. The apparatus of claim 18, wherein the control grooves extend substantially parallel to each other, except for a feeding zone of the blanket and a discharge zone for the rotation body.