DE1900953A1 - Method and device for waves of cable sheaths or the like. - Google Patents

Description

Pirelli General Cable Works Limited in London / Great Britain,

Method and device for corrugating cable sheaths or the like.,

The invention relates to a method and an apparatus for corrugating cable sheaths or pipes from permanent

deformable material. f

j It is known for the helical corrugation of pipes, j

especially cable sheaths, to use a ring-shaped tool, which is rotatably mounted in a tool head rotating around the pipe axis with a ball bearing, against the pipe axis,

* ■ i

is radially displaceable with a guide frame and has an inwardly projecting rib on the inner edge, which is in one of the Screw pitch corresponding inclination to the radial plane of the pipe is arranged. The contour of the corrugation is determined by the profile of the deformation rib and the slope of the Corrugation due to the ratio between the speed of the ring

LaIi ₁

shaped tool and. the longitudinal advance of the cable jacket and determined by a slight inclination of the tool from the plane perpendicular to the longitudinal axis of the cable jacket.

oofttot / ona

ORfGfNAL INSPECTED

It is also known, the radial adjustment of the tool to the pipe axis or to the axis of the cable jacket, which the shaft depth determined, either by means of an adjusting screw arranged on the rotating tool head or by means of an axially displaceable one Perform inclined surface cams, this latter adjustability has the advantage that the adjustment of the Can perform eccentricity without stopping the rotating tool head.

Finally, it is also known to provide a pipe or a cable jacket with annular ./eilungen axially one behind the other, in a way that differs from the helical corrugation to be produced in a continuous operation. This annular corrugation has certain advantages over the helical corrugation. In particular, it results in a better flexibility of the corrugated tube or cable sheath, facilitates the production of coupling connections and the mounting terminal crimping _f and also gives a better safety against the penetration of moisture and their transmission along the cable. However, it has hitherto been difficult to make the annular corrugation in a continuous operation with constant and uniform advancement of the tube or cable jacket to be corrugated. _;

The invention is based on the object of the known device for the helical corrugation of cable sheaths in to change a continuous operation so that they are with a uniform axial feed of the pipe or cable jacket

009908/0242

ORlGiNAL INSPECTED

can also be used to produce an annular corrugation. In this case, compared to known devices for producing an annular corrugation, in which either the axial advance of the tube or cable jacket to be corrugated is interrupted during the work of the corrugating tool or the corrugating tool is also conveyed and then moved back to a starting position ^! must be moved back, by avoiding this temporary interruption of the corrugation process a considerably increased j

Work performance of the corrugator can be achieved.

This object is in waves of tubular workpieces, wherein the workpiece with simultaneous relative ■ longitudinal movement and relative rotation between workpiece and tool, an annular deformation - by running tool that is eccentrically offset with its axis to the workpiece axis j and an inner deformation rib on the periphery of the work j piece comes to rest, according to the invention in that the inner deformation rib of the annular tool has such a curvature) shape and position and the simultaneous relative longitudinal and rotary movements of both parts are coordinated such that in the circumferential direction successive parts of the deformation rib in planes at right angles to the workpiece axis press against parts of the outer surface of the workpiece that follow one another in the circumferential direction. The curvatures of the tube or cable jacket to be corrugated and the surface of the deformation rib that comes into engagement with it run in the same direction, while with previously known anor'dnun-

009808/0242 _BA0

gen, e.g. according to British patents 896 I63 and 1 051 ^ 29, the deformation rib one to the curvature of the tubular Has workpiece opposite curvature. Accordingly, the deformation rib and the workpiece to be corrugated also lie at a smaller angle together, resulting in a simplification of the corrugation device and a reduction in the Shafts required force result.

The device used to carry out the method according to the invention is in a known manner with a tubular one The ring-shaped tool surrounding the workpiece is provided with an inner deformation rib on the outer surface of the, Workpiece comes under pressure to the plant, with drive devices to achieve a simultaneous relative longitudinal movement in the direction of the pipe axis and a relative rotation between the tool and the workpiece are provided and the deformation rib of the tool has such a curvature, shape and position that when passing through the tubular Workpiece through the annular tool successive parts of the deformation rib, their inner radius of curvature is equal to or greater than the maximum outer radius of the corrugated tube, in planes at right angles to the workpiece axis press the workpiece and thereby form successive annular indentations in the workpiece.

The deformation rib is preferably better known to sipli In a helical manner, the ring body carrying it is preferably also eccentric in a manner known per se

'.. 009808/0242

I »* t t ft»

arranged to the pipe axis. In this case, the radius of curvature of the deformation rib is constant and according to the size of the Measure the eccentricity greater than the radius of curvature of the non-corrugated pipe or cable jacket. Goes through the ear then press the ring body rotating around it relative to it Parts of the deformation rib against the outer surface of the pipe, the feed of the pipe being the axial feed of the successive parts of the deformation rib along the tool axis. The deformation rib presses thus momentarily against the tubular workpiece in a direction which is perpendicular to the workpiece axis, so that im Workpiece instead of a helical indentation, an annular indentation is created.

The helical deformation rib only needs to have one turn, so it only needs to enclose the workpiece once. In this case, a complete annular corrugation occurs when the front end of the deformation rib comes free from the workpiece and the rear end of the rib begins making the next annular indentation. However, if the corrugations are to be particularly even, but can also be "longer" be as a complete turn and extend over two or more turns, fder following the first turn Part of the deformation rib essentially serves to create the annular shape produced by the first turn 'To smooth out indentation.

ORIGINAL INSPECTED

00 * 800/0242 - -

In a different embodiment, the annular deformation tool also have two or more helically arranged deformation ribs, which then have two or more ring & produce shaped impressions at the same time, if necessary one after the other, if each helical deformation rib only over part of the circumference of the annular deformation tool extends.

The exact cross-sectional shape of the helical deformation rib depends on the shape of the corrugation to be produced. This shape and the cross section of the deformation rib must, however, be designed in such a way that the successive parts of the deformation rib when protruding from the of them produced indentation do not hinder the longitudinal advance of the side wall of the indentation. Furthermore, the relationship must between the maximum outer radius of the corrugated ear and the radius of curvature in the plane of the annular body of the deformation rib correctly dimensioned, since this depends on the time during which the successive parts of the deformation rib in the haum between the upper edge and the lower edge of the corrugation remain.

According to one embodiment of the invention, the ring-shaped tool is about the axis of the Hohres to be corrugated in a to the tube », axis rotatably mounted in a right-angled plane, with independent drive means for the axial advance "of the Hohres dureh the ring-shaped tool and for turning the tool. will see.

009808/024 2 original inspected

However, it has been found that the effectiveness and applicability the method according to the invention and a device operating therefrom are in some cases modified can, if the annular deformation tool around the too corrugated tube revolves in a plane that corresponds to that of the tube axis perpendicular plane is inclined by an angle of attack in such a way that the rotary movement of the annular .Werkzeuges at the same time also the axial advance of the tube to be corrugated relative to the Tool generated. ,

The ring-shaped tool has an oiler several helical ones Deformation ribs, the angle of inclination of the or each helical deformation rib should be smaller or equal to the vorer.kanten setting angle of the ring-shaped tool be. When using a suitable angle of inclination or inclination, the device can also be used according to the British patent specification 791 313 £ ur execution of the method according to the present invention, provided that only the tool is used according to the present invention required execution. ;

In practice, the inclination of the ring-shaped tool to the axis of the tube or cable jacket to be corrugated is approximately at an angle of k - 8 °, usually approximately 5 °, but other angles of inclination can also be considered, especially if the tool is more than a helical one Has deformation rib,

Does the annular tool have one or more left-handed

009808/0242 bathroom original

helical deformation ribs and it is seen in the direction of the longitudinal movement of the pipe, opposite to the direction of rotation If the clockwise rotation is offset, the tool receives one arranged in the opposite direction to the direction of rotation of the clockwise Inclination from the plane perpendicular to the pipe axis, seen in the transverse direction in which the tool axis is relative to Pipe axis is offset eccentrically.

fe The opposite is true when equipping the ring-shaped tool with one or more right-hand deformation ribs and when this tool is rotated, in the feed direction of the Pipe, in the direction of rotation of the un-pointer the ring-shaped tool from the plane perpendicular to the pipe axis in the direction of rotation of the clockwise inclined, namely with respect to the direction in which the tool axis to the axis of the shaft to be turned Rohres is offset eccentrically.

In a further embodiment of the invention, the feed movement of the workpiece and the relative rotational movement * 'between the tool and the' workpiece can be driven by a common drive motor and a control device can be provided which automatically maintains a predetermined ratio between the feed speed of the workpiece and the Speed provides the relative rotation regardless of changes in engine speed.

009608/0242 bathroom original

t t l · i

19P0953

The drawing shows examples of the implementation of the device according to the invention and those essential to the invention used in it Individual parts, namely show

Fig. 1 is a longitudinal section through one in the device used deformation tool,

Pig. 2 an end view of this tool,

3 shows the schematic side view of a machine which is equipped with a tool according to Fig. 1 and 2,

Fig. ^ The diagrammatic oblique view of the end face a modified deformation tool with a part of a cable jacket located therein,

Fig. 5 cLie side view of a portion of a with this Deformation tool of corrugated cable jacket,

6 is a perspective, schematic view of an annular deformation tool with a left-hand rotation Deformation rib and a part of a cable jacket located in the tool,

Fig. 7 is a perspective view of the same parts, but with a right-hand deformation rib of the movement. witness,

Fig. 8 is a horizontal longitudinal section through one with the Deformation tool according to Fig. 6 provided tool holder a deformation machine in the view from above and

9 shows a vertical longitudinal section of the same parts in a side view.

Ö09ÖO8 / Ö2U ORIGINAL INSPECTED

► · · · » tti

- 10 -

The deformation tool according to FIGS. 1 and 2 consists of an annular body 1 which has a helical deformation rib contains, which extends over two full turns. The deformation rib 2 has between two successive turns a slope which corresponds to the distance between two annular corrugations of the cable jacket 3, which in Pig.l is indicated with dashed lines.

In a first embodiment of the crimping device according to the invention, the ring body 1 is arranged perpendicular to the axis of the cable jacket 3> with its axis therefore parallel to the axis of the cable sheath coaxially in an unillustrated ball bearing \ which in turn is rotatably mounted coaxially in one! Carrier block sits. This support block is provided with an adjusting device with which the eccentricity of the axis of the ring body 1 to the axis of the cable jacket 3 to be corrugated can be adjusted in order to change the corrugation depth as required. The cable sheath 3 is held on both sides of the ring body 1 in coaxial guide sleeves.

When the device is in operation, the ring body 1 is rotated eccentrically about the axis of the tubular cable jacket 3 and the cable jacket continues in its longitudinal direction at the same time «

continuously advanced through the ring body 1. There are successive Parts of the helical deformation rib with the cable jacket engage and deform successive ones Parts of its scope. The axial feed rate / of the cable jacket 3 is now depending on the speed

009ÖÖÖ70242 bad original

of the ring body i dimensioned so that the advance of the cable jacket with the axial speed of movement of the point of contact the helical deformation rib 2 on the cable jacket when the ring body 1 is rotated. Is this the case, the tool does not make a helical, but an annular indentation in the cable jacket for each Rotation of the hanging body 1 made. When the leading edge of the deformation rib 2 during the eccentric rotation of the tool just getting free from such an oath begins the rear edge of the deformation rib 2 with the manufacture of the next annular indentation.

With this version of the deformation machine, separate, synchronous drive drive to advance the Cable sheath through the hanging body and for rotating the hanging body 1 are provided.

If the device according to the invention is to be used in order to corrugate a cable jacket at the same time as it is manufactured, i.e. not the corrugation on a prefabricated one To make pipe or sheathed cable of a certain length, it may be necessary to provide additional funds for mutual Control of the position of the corrugating device and the speed of rotation of the ring body 1 plus the sheathing device provide that supplies the cable sheath. This delivery speed can be irregular, in particular bet manufacture of the cable jacket on a hydraulically operated Extrusion press from which the cable jacket, e.g. made of aluminum

009808/0242

minium ^ in the strand is pressed against the cable.

In this case, the corrugating device equipped with the deformation tool, which is denoted by A in FIG. 3, is arranged immediately in front of the hydraulically operated extruder 4, from which the cable with an oversized cylindrical cable jacket 3 produced by the extrusion press runs. In this case also a device for synchronizing the rotational speed of the Bingkörpers 1 with the variable speed of advance of cable sheath 3 provided ψ.

The hanging body 1 is powered by an electric motor 5 via a Gearbox 6 driven at constant output speed. The electric motor 5 also drives a feed device 7 a speed change gear 8 on. The feed device has two conveyor belts, which form a passage for the corrugated cable jacket and of which the lower conveyor belt driven, but the upper conveyor belt running freely and for clamping the corrugated cable jacket with a screw spindle is vertically adjustable.

Parts A, 5, 6, 7 and 8 are fixed to a support plate mounted with wheels 10 along a cable jacket 3 parallel guidance on stationary rails 11 of a work table 12 is movable. The mobile support plate is through a pull cable or in some other way connected to the actuator of a variable resistor 14- that controls the speed of the electric motor 5 changed. If the support plate moves towards the extruder 4, then ife re -G from the control resistor 14

009808/0242

diminished, / 'that lo · finally to still

stand comes. If it moves in the opposite direction, i.e. away from the extruder k , then -irga.

to, up to a certain limit. The pre-thruster 7 has the task of changing the speed ■ gear 8 to the required ratio between the rotational speed of the ring body, not shown in Fig. 3 1 and the speed of movement of the conveyor belts of the feed device 7. This speed ratio is then maintained regardless of any * changes in the speed of the electric motor 5.

As soon as the molding press 4jnit the production of the cable jacket begins, the feed device 7 is brought with its conveyor belts on the cable jacket 3 to rest.

Is the cable sheath 3 is moving faster than the feed device 7, the support plate 9 is NIIT all it befe- j stigten parts in the feed direction is moved forward _t until the I speed of the feed device by the Begelwiderstand 14 increased so that it with the Fördergeechwindig- j speed of the cable jacket 3 corresponds. The support plate 9 then remains in this position until a change occurs in the conveying speed I of the cable jacket 3. J the cable jacket 3 moves initially or the feed device at any other time long 'more slowly than the conveyor belts 7' so that the supporting plate 9 is withdrawn with the parts thereon to extruder 4, thus using the rheostat 14

000008/0242 ORiGi _NAL INSPECTED

a reduction in the speed of the drive motor 8 takes place. With all these speed changes, the ratio remains the linear speed of movement to the speed of rotation of the ring body in the holder A is constant, so that the shaped windings of the cable jacket are also the keep the same distance from each other.

The tubular cable jacket 3 to be corrugated is proportionate thick, then the ring body 1 is subject to a considerable SSiiwfBionstress when the cable jacket is corrugated. In order to counteract this stress, the corrugating device can be followed by a second corrugating device Ring body 1 rotates in the opposite direction to the ring body 1 of the first corrugating device. The deformation rib 2 of the second Ring body 1 naturally run in the opposite direction to that of the ring body of the first corrugating device. The ring body 1 of the second Corrugating device does not form a new corrugation, but rather it is guided with its deformation rib in the wave troughs the corrugation already produced by the first forming tool, smooths it and at the same time creates an opposing torsional moment.

For the arrangement described, a power drive is required to drive the cable provided with the cable sheath through the device, since the force exerted by the deformation rib 2 on the cable sheath 3 acts in the opposite direction to the direction of movement of the cable sheath, which is shown in FIG . _v l is identified by the arrow M.

_v> ; p Ift8 08/0242 originally inspected

It has been found that a special drive to advance. thrust of the cable can be omitted if the axis of the ring body 1 is inclined to the axis of the cable jacket by a small angle ° C , which must at least correspond to the pitch angle of the helical turn of the deformation rib (see Pig. ^ · and 5) · With this axial Inclination of the ring body 1, the deformation force acting on the cable jacket has an axial component F which, according to FIG. The angle of inclination ^ should not be smaller than the angle of inclination of the helical deformation rib 2 of the annular body 1, so that a self-propulsion occurs through which the cable provided with the cable sheath 3 is advanced without an additional drive device. The angle of inclination oC is about 5 °.

Fig. 6 shows schematically the direction of rotation R of the ring body 1, the advance direction M of the cable jacket 3 and the angle of inclination vC of the ring body 1, unless the helical rib 2 is left-handed. In the advancing direction M of the cable jacket seen, the iiingkörper 1 is oppositely displaced relative to the cable jacket 3 to a clockwise direction in Uralauf. The axis of the label jacket 3 eats with CC, the axis of the hanging body 1 with DD ¹ indicated. The axis DD ^{1 is} not only inclined to the axis CG ^{1 of} the cable jacket by the angle, but is also offset eccentrically to it, the direction of displacement being through the PTeii '^ aagedeutec, so that. the helical deformation rib 2 cen cable jacket 3 in.

009808/0242 BAD original

touches a point P at which the deformation rib 2 lies in a plane perpendicular to the cable jacket axis GC in order to form a sequence of annular waves 15 in the cable jacket 3 ^ u. The axial distance between successive waves, i.e. between the resulting wave troughs, is equal to the slope of the helical deformation rib 2 length of the line PP !.

Of FIG. 6 can be deduced that the opposite directions s is inclined for achieving seen from the direction perpendicular to the cable sheath axis, in the direction of the eccentric movement E by the angle "6 before * · mentioned self-drive of the annular body 1 to the rotational direction of the watch, wherein oC is greater than or equal to the pitch angle of the helical deformation rib 2.

, Fig. 7 shows the relationships between the direction of rotation R of the ring body 1, the direction of advance M of the cable jacket 3 »the direction of the eccentric offset E and the direction of inclination of the angle oC for a ring body 1, which with a ^! right ε common deformation rib 2 is provided. In the BEWE H supply direction of the cable jacket seen, the annular body is χ in the direction of rotation of the watch in circulation added, and it is seen in the direction of the eccentric offset E, AUB the axis perpendicular "GC of the cable sheath plane about öineh

009808/0242

ORIGINAL INSPECTED

Angle Λ / inclined in the direction of rotation of the clockwise.

8 and 9 show an example of the practical implementation of the invention in two offset by 90 ° to each other lying longitudinal sections through the bracket of the hanging body.

The cable sheath 3 indicated in FIG. 9 with dash-dotted lines is held in the desired direction of passage by two guide bushings 16, 17 which run in associated ball bearings 18 and 19, respectively. The hanging body 1, which has the embodiment shown in Fig. 6, is ^{rotatable about its axis DD 1 there} in a ball bearing 20, which in turn sits with its outer race 21 in a rotatable head 22,

i which is only partially visible. The race 21 is with the bing body 1 in the head 22 in one to the axis of rotation of the head j right-angled plane in the transverse direction, the axis of rotation of the head 22 with the axis C-C of the cable jacket matches.

To change the eccentricity of the axis of the bing body ^s t

1 with respect to the axis of the cable jacket 3, the head has j two Sfeellnocken 23 on opposite sides, which with to the axis C-C of the cable jacket inclined, mutually parallel inclined surfaces are provided »The adjusting cams 23 are i» Head 22 together axially displaceable and are ^ e. by a Support roller 2 ^ which unites in a cylindrical circumferential groove the outer race 21 receiving bing body is guided, with this ring body in connection.

ORIGINAL INSPECTED

If the adjusting cams 23 are moved together in the same axial direction, a transverse movement of the takes place Hing body 1 with respect to the axis of the cable jacket 3 instead, through which the depth of the V / ellungen can be regulated. the Inclination of the ring body 1 from the plane perpendicular to the axis of the cable jacket is shown in FIG. 9 by wedge-shaped clamping pieces 25 determined between the flanges of the head 22 are tense.

QaMOi / 81t 2 originally inspected

Claims (6)

Claims 1. A method for the annular corrugation of tubular workpieces, in particular cable sheaths, in the case of equilateral relative longitudinal movement and relative rotation between workpiece and tool, the workpiece is an annular Deformation tool goes through, das.mit an inner deformation rib comes to rest on the circumference of the workpiece, characterized in that the inner deformation rib (2) such a curvature, shape and position and the simultaneous relative longitudinal and rotational movements of both parts are coordinated so that successive in the circumferential direction Parts of the deformation rib (2) in the factory stüokachse right-angled planes against in the circumferential direction '' successive parts of the outer surface d-> e workpiece (3) to press. 2. The method according to claim 1, characterized in that with known helical design and for Workpiece axis eccentric arrangement of the deformation rib (2), the axial relative movement between the tool (1) and the '· ^; Ii "Workpiece (3) is set in such a way that it is with the j The axial rate of progression of a contact point of the deformation rib caused by the helical pitch of the deformation rib coincide with the relative rotation of the parts (1,3). 3. The method according to claim 1 or 2, characterized in that the axis (DD ¹ ) of the annular tool (1) to the axis 009808/0242 Original inspected (CC ¹ ) of the tubular workpiece by an angle {cc) is inclined in such a way that the relative axial movement between the tool (1) and the workpiece (3) is generated by the relative rotary movement between the two. '. " 4. Apparatus for carrying out the method according to claim I ₁ 2 or 3 with an annular tool surrounding the tubular workpiece, which comes with an inner deformation rib on the outer surface of the workpiece under pressure to the plant, 'wherein drive devices to achieve a simultaneous relative longitudinal movement in the direction the pipe axis and relative rotation are provided between the tool and the workpiece, _t characterized in that the Verformungerlppe (2) of the tool (1) has a curvature such Ge.stalt and location ": indicates that when passing through the tubular workpiece ( 3) * through the annular tool (1) successive parts ^ j of the deformation rib (2), whose inner radius of curvature is the same * or greater than the maximum outer radius of the corrugated Batst * «« (3) ', in planes at right angles to the workpiece axis against the work «" ■ ". ^4th Press j piece and thereby successive ring-shaped | Form indentations in the workpiece. . ? 5. Apparatus according to claim k, characterized in that that 'the ring-shaped tool (1) is eccentric to the axis of the v @ & t ~ .' Föraigen workpiece (3) stored iet. <? . ■ 6. Apparatus according to claim 5, characterized in _{that f} that the deformation rib (2) of the tool (1) is a helical, -. Has a slope, · "■ * ■ '.- 2 :, 009808/0242 originally inspected u ♦ 4 · · O · · t I - 21 - 7. Apparatus according to claim 6, characterized in that the helical deformation rib (2) located in the annular tool (1) is at least the length of a complete one Having viinding. 8. Apparatus according to claim 6 or 7 * characterized in that the annular tool (1) or at least two has more helically extending deformation ribs (2), which simultaneously produce two or more annular impressions on the tubular workpiece (3) or one after the other on the Workpiece come to rest - if each is helical Deformation rib only over part of the circumference of the annular Merkstückes extends. 9. Device according to one of claims k - 8> characterized in that the annular tool (1) is mounted in such a way that it revolves around the tubular workpiece (3) in a plane at right angles to the workpiece axis, with independent drives (6 and 7, respectively * 8} for generating the rotary movement; äe3 riagföraiegen tool (1) and top feed of the tubular workpiece (3) provided. 10. Device according to one of claims H- r 8 _f gekeiraseiohnet that the riagföraige Merkzeug (1) is mounted such that © s UOi <äas rahrt'armXge workpiece C3) in a Sb © »@ circulates j the ru & er Badial plane at right angles to the Merketüokachse at @ in.% »angle of inclination Ce ^) äerart inclined, öaö ä @ r axial feed of the tubular workpiece (3) eyreii the Brettting deg ringföra & gen tool Cl) is generated. ORIGINAL INSPECTED - 22 - 11. The device according to claim 6-8 and 10, characterized ', that the pitch angle of the or each helical deformation rib (2) is less than or equal to the angle of attack of the annular tool (1) is. 12. Apparatus according to claim 10 or 11, characterized in that the angle of attack '{d ) of the annular tool (1) is about 5 °. 13. Apparatus according to claim 11 or 12, characterized in that with respect to the relative axial feed of the workpiece (3) the helical deformation rib (2) of the ring t-shaped tool (1) has a left-handed slope, m & the tool 1) rotates in the opposite direction to the clockwise direction of rotation and out of the radial plane at right angles to the workpiece axis with respect to j the relative offset of the tool axis (D-D ') to the axis ! (CC ¹ ) of the tubular workpiece (3) is inclined in the opposite direction to the clockwise direction of rotation (Fig. 7) » fc 14 ·. Device according to claim 11 or 12 ,. characterized by this. marks »that with regard to the relative axial feed of the work- {J% the helical deformation rib (2) äea ring-Merkzeuges CD has a right-hand slope ^. the tool (1) rotates clockwise and out of the Merkstüekaehse right-angled sadial plane with respect to the Offset of the tool ^{axis (DD 1} ) to the axis (C — C ^ J of the tubular work piece (3) in the clockwise direction of rotation is shown in Fig. 8). ORiGiNAL INSPECTED 15. The device according to claim 5 or one of claims 6-14 in conjunction with claim 5, characterized in that that the ring-shaped tool (1) is mounted in a rotating tool head which, in a manner known per se, is axially displaceable adjusting cam (23) is provided for changing the eccentricity of the tool (1) to the workpiece. 16. Device according to one of claims 4-15, characterized characterized in that the feed movement .des workpiece (3) and the relative rotational movement between the tool and the Workpiece are driven by a common drive motor (5) and a control device (9,10,14 ·) for automatic Maintaining a predetermined relationship between the linear feed rate and the speed of the relative Rotation is provided regardless of changes in engine speed. ORfGlNALfNSPECTED 009808/0242 ZH L e r s e i t e