FR2864799A1 - Removable cutting plate comprises plane/cone frontal ramp having rack coupled with flange on cutter, which is inclined to the side of the support and turned opposite to corner for separating sides of framing by the force exerted by flange - Google Patents

Abstract

The frontal ramp comprises: two sections, which extend and inclined in planes; and rack for coupling with the slide. The framing side (5) extends to transverse direction of the frontal ramp (14), is contacted with housing (40) of the cutter and glides by corner effect and folded back to extend an acute angle to the side of support (2) to form wedging rostrum. The plate having a curvilinear cutting edge (13) for lateral and end attack and anti-loss bearing thrust (18, 19) of the slide. The ramp is located at the shoulder end of guidance of fastening section of the slide. An independent claim is also included for a cutter.

Description

The present invention relates to a cutting insert and a cutter

corresponding.

  For machining a workpiece, a milling cutter is conventionally carried with two cutting inserts clad and attached to respective bottom surfaces of two axially opposed radial housings. Each bottom surface has at its center a tapped fixing hole in which is engaged a clamping screw, passing through a smooth fixing hole formed in the thickness of the plate, to press a bearing surface thereof on the background.

  However, since the screw has a certain lateral clearance with respect to the tapping, to facilitate the screwing, such a screwing can control only one degree of freedom in translation, in the "vertical" direction to keep the support face pressed. of the plate in the plane of the bottom of the housing.

  To control the other two degrees of freedom in so-called horizontal translation, in its plane, that is to say, to accurately frame the plate relative to its desired position on the bottom, and also to avoid parasitic rotation thereon, the housing further comprises two lateral sides on which abut two flanks of the wafer.

  However, the framing precision is limited because the necessary clearance between the screw and the tapping is found laterally between each side and housing side facing.

  The present invention aims to provide another solution for clamping the wafer, offering better positioning accuracy thereof and / or a simpler clamping mechanism.

  To this end, the invention relates first of all to a removable cutting insert comprising fastening means provided for cooperating with clamping means associated with a cutter in order to press a bearing face of the insert on the bottom of the cutter. a housing of the milling cutter, characterized by the fact that the fixing means comprise a frontal ramp of deflection, inclined with respect to an extension plane of said bearing face and turned, at least partially, to the opposite a flanking of the wafer, the front deviation ramp being arranged to deviate, in the direction of the side of the frame, a thrust force exerted by a clamping slide mounted on the cutter.

  Thus, the slider is a movable jaw ensuring the control of at least two degrees of freedom in translation, respectively vertical and horizontal, since it exerts on the wafer, due to the inclination of the front ramp, a component force transversal, here called vertical, the plating on the bottom, and component in its extension plane, plating the sidewall on the side of framing, serving as a stop opposite.

  Furthermore, the wafer can thus be free of any fixing hole, which simplifies the manufacture. The front ramp may for example be located on an upper face, accessible, opposite to the bearing face, or be located on a front or side flank, that is to say opposite to the side of the frame. In particular, the front ramp may be a chamfer connecting the upper face to the leading edge, if the cutting edge front and / or side associated allows it. The front ramp, which, unlike the fixing hole, constitutes an external relief that is to say accessible, protruding or in the form of a groove, can, in any case, be obtained gross manufacturing, so no extra cost, although a correction is not excluded.

  It will be noted that the front ramp, whose function is to be able to receive a pushing force or pressure on the part of the slider, provides this function in that its surface includes a so-called horizontal component and a so-called vertical component. , depending on the thickness of the wafer. Assuming no friction between the slider and the frontal ramp, the pressure force is normal to the surface of the frontal ramp, so that the slope of the frontal ramp then determines, to 90 degrees, the direction of the force pressure.

  The function of the frontal ramp can be ensured by a static support cooperation of the slide on the frontal ramp, a sliding of the slide on this one intervening only in case of elasticity, for example by bending the slide, or to, if necessary, push the plate horizontally without effort if it is not yet in final stop position. The frontal ramp can therefore be a smooth, monotonically sloping surface on which the slide can slide, or a grooved surface on which, being unable to slide transversely to the splines, the slide exerts a force of pressure on two surfaces of the groove representing the two components above the slope of the frontal ramp.

  The frontal ramp may be substantially flat, in particular if the corresponding driving part of the thrust, belonging to the slide, is translated only, without rotation, which makes it possible to give it a shape having a bearing surface area, limiting the wear compared to a rotary contact, so only on a generator.

  The frontal ramp may, however, be in the form of a truncated cone sector, particularly if the slide is translated with rotation on itself.

  Whatever its precise shape, the front ramp may comprise at least two sections functionally in parallel. The support of the slider is thus provided on two generatrices, or even two sliding surfaces, forming two laterally spaced skids, which limits the wear and contributes to better stabilize the wafer, the bearing forces of the latter acting in two places laterally spaced on the bottom of the housing.

  Preferably, the two sections extend generally in respective mutually inclined planes. The two sections thus constitute two mutually lateral facets, joined or distant, of the same fictitious funnel surface, forming the two branches of a V or U with substantially rectilinear or rounded flanks in frustoconical shape. As a result, in addition to receiving the so-called vertical thrust towards the bottom and toward the registration flank, thus controlling respectively the first two degrees of freedom in translation, the front ramp also ensures, by its laterally facing facets, a centering relative to the direction of sliding on the bottom, that is to say the control of the third degree of freedom in so-called horizontal translation, insofar as the slide is well guided.

  It can also be expected that the difference in inclination above relates to the longitudinal direction, of slope of climb on each facet, so that the slide, then mounted so as to be able, in addition to its translation generally in the desired direction, slightly pivoting parallel to the bottom, will tend, during its progression in sliding, to repel more strongly the facet with the largest inclination slope. As the facet considered also has a lateral inclination, this "axial" pushback by the sliding force will further generate a lateral pushing component, which can therefore be used to push another side of the framing flank, against another side of framing of housing. Such an aspect is developed further.

  The frontal ramp may have a decreasing inclination towards a summit zone thereof.

  The frontal ramp, thus having a decreasing angle of rise or decreasing wedge, allows the slide to develop the same sliding work over an increased length, that is to say that the user can exert only one force limited drive, due to the amplification of plating force obtained by reducing the angle of climb. This equates to a progressive "change of speed", the clamping being thus facilitated. On the other hand, as the final angle of rise is limited, this angle is more easily within a theoretical angle determined by the coefficient of friction between the front ramp and the slide, the holding in position of clamping is thus better secured against vibrations.

  The front ramp can be at least partially turned away from a corner separating two sides of framing. This embodiment corresponds to one of the two facets discussed above.

  The framing flank is advantageously folded down to extend substantially at an acute angle, with respect to the bearing face, so as to form a wedge or wedge of the wafer against a framing abutment side, preferably in shape. complementary.

  The wafer thus has two opposite end ramps, forming a dovetail clamped by the movable jaw slider.

  The plate is thus maintained plated in two zones, namely the zone of the frontal ramp and the zone of the sidewall, which ensures the locking of the first two degrees of freedom in translation, that is to say in the direction the thickness of the wafer and in the direction of sliding.

  The alignment flank may further extend generally in a direction inclined relative to a direction of transverse extension of the frontal ramp, direction of transverse extension itself substantially perpendicular to the direction of sliding. Thus, the registration flank, after coming into contact with a framing side belonging to a housing of the cutter, can slide by wedge in an oblique direction with respect to a direction of sliding of the slider.

  The wafer thus follows a path with two mutually inclined sections because, once reached the first stop, for example rear, by a sliding substantially along the direction of sliding, the wafer, by a radial movement, slides towards the second stop, which ensures the lateral locking, or third degree of freedom, of radial translation parallel to the bottom.

  The wafer may have a curvilinear cutting edge for lateral and end etching, for example for a hemispherical size.

  Advantageously, an upper face of the wafer comprises a stop against loss of the slide.

  The front ramp is advantageously located at the end of a shoulder, possibly belonging to a groove, for guiding a clamping section of the slide, which is formed by a lateral flank extending in a direction inclined with respect to a longitudinal flank. of the wafer, thereby forming a corner of lateral misalignment of the wafer. Along the groove, the lateral flank can twist so that a final section of it forms the front ramp.

  The invention also relates to a milling cutter comprising clamping means, against the bottom of a housing, a removable cutting insert with front ramp according to the invention, milling cutter characterized by the fact that the clamping means comprise means for guiding and holding in position a slider pushing the front ramp to a housing-limiting framing side and arranged to serve as a framing stop of an associated framing flank of the wafer.

  Although the plate has only very simple means of attachment, namely the front ramp, the cutter does not require complex clamping means, the slide, removable or not, and its guide means constituting very simple means.

  Guiding provided by the guiding means must at least maintain the slider pressed on the front ramp, that is to say that it can be provided that the slider has a limited play in height on the front ramp, and that it can rotate further in a plane parallel to the bottom or even shift laterally while still resting on the front ramp.

  The slider may for example be mounted on the cutter by means of a return spring of the slider to a predetermined final position, preferably located beyond the position of the actual final position, so that the spring continues to exert a holding thrust in the actual end position. The spring, for example of the blade type, can further ensure the desired guidance so that the trajectory of the active surface of the slide always passes through the front ramp. The spring can in particular be recalled in the armed position, unlocking, by an external tool operated by the user, such as a force amplification lever, and able to overcome the possibly high force of the spring. However, it can be expected that the centrifugal force of the cutter generates all or part of the pushing force and holding the slide in the final position of framing.

  The guide and retaining means, which could be reported on the cutter, are however preferably integrated, for example in the form of a guide hole of a section of the slider associated with a clamping section comprising a frustoconical head cooperation with the frontal ramp.

  As explained above, the guide hole is not necessarily of cross section totally adapted to that of the slide, for example cylindrical in the case of a screw, but it can be widened parallel to the plane of the bottom of the housing, the two high and low walls providing the guide for holding the slide to the desired height. For driving and maintaining the end position of the slider-screw, at least one of the two walls above may comprise a rack engaged with a crenellated generator of the screw.

  Note that the rotation characteristic of the cutter does not intervene to define the essential characteristics of the invention indicated above, so that it is also applicable to a fixed tool holder.

  The guide hole is preferably, as mentioned above, tapped to further serve as axial drive means, and holding in the final position, when the slider is in the form of a screw.

  In such a case, the frustoconical head is advantageously rotatably mounted relative to the guided section.

  The bearing surface of the head on the front ramp may thus include a shaped surface adapted to the front ramp, which limits wear.

  In one embodiment, the guide hole forms an axial position-holding cavity of the slider, the recess having a lateral extension for guiding said guided section in rotation and axially enclosing a lateral protuberance thereof, that is to say - Say a kind of leg with a bulge such as a foot with lateral extension, and said frustoconical head carries a lateral thread provided to cooperate with a rack carried by the front ramp.

  The slide is thus axially fixed, hooked to the cavity, and its rotation, in a direction of unscrewing, tends to attract the rack towards the cavity, which ensures the desired blocking of the wafer. The cavity is for example widely open laterally facing the housing of the wafer to initially receive the protrusion, the lateral opening extending axially forward, that is to say towards the housing, by a narrower slot , for the passage of a "neck" bearing the protuberance. The cavity thus forms a sort of laterally split funnel, trapping the foot of the slider. The wafer, placed in place, thus attracts, by the rack, the slide towards the top of the funnel, where the lateral slot is narrower, and thus prevents any lateral exit of the slide from the cavity.

  The cavity preferably has an elongate shape, cylindrical or preferably with a section, on the side of the axial mouth, generally conical, possibly with a variable conicity depending on the axial position, with a top turned towards the mouth, to maintain the slide according to the desired axial direction. In such a case, the guided section, then at the end of the slider, is introduced laterally into the cavity and then slides slightly, at the outlet towards the mouth, until its protrusion abuts on the conical surface portion.

  The guide hole may thus comprise laterally an axial slot having a terminal widening of initial introduction of the section guided in the holding cavity, the enlargement being located opposite the housing so that the wafer constitutes a closing shutter of the enlargement. of the slot.

  The guide hole may have an extension direction extending in a substantially axial and radial plane with respect to a general axis of the cutter.

  The slider thus exerts a pushing force substantially parallel to the bottom of the housing, so that, even in the case of a coefficient of friction on this bottom, a possible seizure of the slider on the front ramp is not a problem since, as shown above, high, a pushing force is sufficient, because there is no fundamental need for sliding of the slide. If the latter has a direction of movement directed towards the side of the frame, the plate will naturally accompany the slide. Moreover, any slip jamming of the wafer on the bottom of the housing is excluded, since the thrust force of the slide is substantially parallel to this bottom, and the "vertical" force of support on the bottom is only the component misguided. Maintaining the pad against the bottom can in particular be ensured by precisely maintaining the slide in the desired direction. Furthermore, the slider, "horizontal", and can have a large repelling stroke of the wafer, to facilitate the establishment of it.

  The direction of extension of the guide hole is for example substantially parallel to the general axis of the cutter. The risk of the slide sliding against the guide hole, under the effect of the centrifugal force, is thus limited.

  The direction of extension of the guide hole may be substantially perpendicular to the general axis of the cutter or define a direction of insertion of the slide away from the general axis of the cutter.

  The centrifugal force of the cutter thus contributes to holding the slide in position, as explained above.

  The guide means may in particular comprise a guide surface of the clamping section.

  The above guiding surface may be lateral or be located opposite the bottom of the housing to thus constitute counter-support ensuring the maintenance of the slide at the front ramp, that is to say to the desired height by report on the merits.

  The housing advantageously comprises a longitudinal lateral side, radially internal to a general axis of the milling cutter, the side extending substantially in a plane deviating from the general axis when moving away, in the axial direction, from a free end of the strawberry.

  The axial zone of the cutter can thus have, at least beyond a certain distance of axial recoil, a material core sufficiently large to accommodate the sliding hole.

  Advantageously, the housing comprises an anti-stop abutment of the slide, the slider having a determined length and the abutment having two opposite ends limiting a ramp surface oblique with respect to a direction perpendicular to a direction of guide of the slider defined by the guide means, said opposite ends being located, with respect to a current point of abutment of the slide on a mouth of the guide hole, respectively at distances less than and at least equal to the length of the slide.

  The slider can therefore leave the hole completely at an angle, because the ramp surface forms a baffle.

  The bottom of the housing can extend in a parallel plane or inclined on a general axis of the cutter.

  It can thus, according to the inclination, be provided a so-called positive cut or a negative cut. In the event of a positive cutting angle, it is the front end of the wafer, for example in a quarter circle, which comes into contact with the first workpiece, that is to say at the level of the workpiece. general axis, in the manner of a screw attracting the material by twisting penetration. In the case of a negative cut, the material tends to be repelled.

  In such a case, the cutter may comprise another housing having a bottom extending in a plane having an inclination, with respect to the general axis, of direction opposite to that of said inclination of said housing.

  The two associated plates thus exert opposite effects, of attraction and repulsion of the material, which neutralize themselves at least partially, taking into account the value of each angle of inclination and the possible difference in axial and / or radial advance. between the two plates.

  The framing side is advantageously folded down to extend substantially at an acute angle relative to the bottom of the housing and thus form a folding ramp of the sidewall to the bottom of the housing.

  The framing side may further extend in a direction oblique to a normal sliding direction of the slide, to laterally push the wafer relative to the direction of sliding.

  Since the clamping means are very simple, that is to say, not bulky, the cutter can comprise at least three said housings.

  In the case of at least two housings, a first of the housings may be arranged so that a cutting edge of the wafer extends radially to a general axis of the cutter, a second of the housings being arranged so that the associated cutting edge stops at a distance from the general axis.

  It is thus possible to maintain an axial core, separating the housings, sufficient to preserve the solidity of the cutter and possibly to provide the guiding holes of the slide.

  For a so-called shoulder plate, the guide means of the slide are advantageously arranged to define a direction of said guide having, with respect to a longitudinal frame of the housing, an angle less than said corner angle.

  For such a mill thus equipped with such a shoulder pad, the guide means of the slider and the lateral flank of the groove are advantageously mutually offset so that, in an initial stroke to reach the front ramp, the slider, by effect wedge on the lateral flank, pushes, in a first phase, a longitudinal flank of the plate against the longitudinal direction of the side, and that the slider, in a second phase, continuing its stroke to reach and press the front ramp, exerts a lateral clamping force against the longitudinal side.

  In such a case, the slider, the guide means of the slider and the lateral flank are advantageously arranged so that a said lateral clamping force and a frontal clamping simultaneously operate against the said framing side.

  The invention will be better understood with the aid of the following description of a preferred embodiment of a cutter and a cutting insert according to the invention, with reference to the appended drawing, in which: FIG. an axial end view of the milling cutter of the invention equipped with three plates according to the invention, FIG. 2 corresponds to FIG. 1, but in an oblique perspective with respect to the axis of the milling cutter, FIG. partial perspective view representing one of the plates and an associated clamping slider, Figure 4 is a side view corresponding to Figure 3, and Figure 5 is a top view of the plate and a corresponding housing of the cutter .

  FIGS. 1 and 2 show a milling cutter 30 of general axis 31, of symmetry and rotation, comprising, at the end, a plurality of three housings 40, 40B, 40C, which are essentially identical, having respective bottoms 41, 41B, 41C extending in respective substantially axial extension planes, and also radial to the thickness near the associated plates 10, 10B, 10C, with respect to the general axis 31, and substantially equi-distributed around it .

  For brevity of the presentation, only the housing 40 and the associated plate 10 will be described, this description being valid for the other two pairs of such elements, unless otherwise indicated.

  As shown in Figures 3 and 4, the wafer 10 has a large upper face 1 opposite a large bottom face 2, bearing on the bottom 41, and three sidewalls, namely an active side 3, delimiting, with the upper face 1, a cutting edge 13 having, in this example, a curved profile quarter-circle front and side attack for a hemispherical size, a longitudinal flank 4, direction of extension substantially parallel to the general axis 31 and radially internal, which is connected by a corner edge 8 to a rear flank 5, generally radial and axially rear. The bearing face 2 delimits, with the respective flanks 4 and 5, a lower longitudinal edge 24 and a rear lower edge 25, both non-functional.

  The housing 40 has a shape corresponding to that of the wafer 10, with the bottom 41 on which can slide, at least axially, the bearing face 2 of the wafer 10, and with a longitudinal lateral side 44 radially internal, facing which is the longitudinal flank 4, and a rear side 45, generally radial and axially rear, serving as a stop for the rear frame flank 5 when it moves axially rearwardly. In this example, the framing rear flank 5, and the opposite rear side 45, each have, along their length, a succession of several non-mutually aligned ranges to form, in plan view of the housing 40, an approximate framing slot. when placing the wafer 10, one of the above ranges serving as a framing abutment area. Of course, the housing 40 is open laterally and at the end to allow the cutting edge 13 to protrude.

  The plate 10 comprises a front ramp 14, inclined relative to the bearing face 2 and at least partially turned away from the rear marking flank 5, that is to say turned at least partially to the opposite In this example, the front ramp 14 is located in a central zone of the upper face 1. As explained below, the front ramp 14 serves to adjust at least two degrees of freedom of the wafer 10. , namely to frame the wafer 10 in a predetermined axial position with respect to the cutter 30 and to press against the bottom 41.

  To the housing 40 is associated a guide hole 35, here tapped, sliding axis 36 here substantially parallel to the general axis 31 and therefore, therefore, substantially approximately parallel to the bottom 41, and relatively close to the axis general 31, that is to say that the guide hole 35 is drilled in a central core region of the cutter 30. The guide hole 35 receives, on a wall area, a guided portion 55 of a slider clamping device, which is here a screw 50 of axis 51 and guided in axial sliding, the screw 50 further comprising a clamping section 52 for clamping the plate 10 by means of a conical portion head 54 provided to push the ramp 14, and therefore the plate 10, to a framed position, this by substantially axial movement of the rear flank framing 5 until it comes into abutting contact against the rear side 45 of the housing 40. Once arrived in abutment, the clamping section 52 rises on the ram frontal pe 14 sliding thus for wedge effect, press the support face 2 of the wafer 10 against the bottom 41 under stress.

  To ensure a better guidance in the desired direction of translation along the sliding axis 36, the conical portion 54 extends, towards a free end of the clamping section 52, by a cylindrical portion 53 centered on the axis 51 and bearing lateral sliding on a lateral guide surface 43, generatrices parallel to the sliding axis 36, preferably as here cylinder portion, here limiting an external volume located above the housing 40 and reserved for the clamping section 52. Lateral guide surface 43 functionally complements the wall area of guide hole 35, the guide lateral surface 43 forming a raised portion of longitudinal side 44 located above the level of an extension plane of the upper face 1, which plane is substantially radial, as mentioned above.

  In a final phase of clamping after positioning in the square position, the clamping section 52 is therefore, by reaction of the front ramp 14, pushed in the opposite direction to the bottom 41, thus vertically in FIG. 2, possibly with bending in this direction. since the clamping section 52 is cantilevered with respect to the guide hole 35 and furthermore the lateral guide surface 43 can not provide a reaction since it extends here substantially vertically, c i.e. parallel to the reaction direction of the front ramp 14.

  As shown in Figure 2, during the introduction of the screw 50, a free end of the guided portion 55 is first applied to a mouth area of the guide hole 35, however obliquely presenting the screw 50 an abutment surface 19 forms for this purpose a baffle preventing axial presentation. The abutment surface 19, turned towards the rear of the cutter 30, limits a rear portion of an anti-recoil stop 18 with a substantially transverse extension, that is to say a substantially radial extension, designed to prevent the loss of the screw 50. The anti-recoil stop 18 here forms a shoulder or rib projecting from a front zone of the upper face 1.

  Specifically, the abutment surface 19 is here a radial ramp extending obliquely with respect to a radial to the sliding axis 36, that is to say that it has a section, here end, radially internal, located substantially on the extension of the sliding axis 36 and preventing a relative recoil that would be sufficient for the screw 50, already screwed, completely out of the guide hole 35. The abutment surface 19 further has a zone end of "loading" of the clamping section 52, radially external, located slightly more forward of the cutter 30 due to the obliquity mentioned above, that is to say axially further from the mouthpiece area of the guide hole 35, to allow to receive, against the loading end zone belonging to the abutment surface 19, a radial free end surface located at the top of the clamping section 52.

  Alternatively, the stop surface 19, horizontally extended in FIG. 2, may be provided on the cutter 30, and for example here on the lateral lateral side 44, and precisely in front of the lateral guiding surface 43, that is to say, the abutment surface 19 would then have a direction of vertical extension in FIG. 2. The overall principle is thus that of a rifle breech, in which the chamber for receiving a bullet would be size strictly adjusted in length, requiring first position the end of the ball.

  As a further variant, the abutment surface 19 could be located on an upper wall of the housing 40, opposite to the bottom 41, that is to say, be in FIG. 2, on a horizontal rib (18) as drawn, but in high position and integral with the cutter 30.

  In another variant, the abutment surface 19 may be of curved shape in its radial extension direction, with a constant or variable radius of curvature along its extension, and with, as indicated above, a zone substantially facing the sliding axis 36 located at a minimum distance, relative to the rest of the abutment surface 19, with respect to the mouth area of the guide hole 35.

  During loading, the apex, extending in a radial plane of the screw 50, of the cylindrical portion 53 is thus placed on the radially outer end of the abutment surface 19, then the user rotates the screw 50 parallel to the plane of the bottom 41, by pushing the clamping section 52, substantially towards the general axis 31 and more precisely towards the sliding axis 36, and this by substantially radial sliding on the abutment surface 19, which thus constitutes a loading ramp, "up", towards the rear of the cutter 30, the clamping section 52 when it is radially pushed manually towards the sliding axis 36 to reach the desired axial position, focused on the sliding axis 36. This axial position is reached thanks to the fact that the pivoting of the screw 50 makes it progressively penetrate, although still obliquely, into the mouth of the guide hole 35, the penetration advance as a function of the instantaneous pivoting position corresponding to the "axial advance", that is to say the slope, with respect to a normal to the sliding axis 36, of the direction of extension of the abutment surface 19.

  In other words, the plate 10, or alternatively a wall of the housing 40, comprises the anti-recoil stop 18, anti-loss of the screw 50 which has a predetermined length, anti-recoil stop 18 comprising, between two ends opposite, the abutment surface 19 ramp obliquely to a direction perpendicular to the sliding axis direction 36 of the screw 50, the opposite ends above being located relative to the mouth area of the hole of 35, and precisely with respect to an instantaneous point, or current, of abutment thereon, at respectively slightly smaller distances and at least equal to the length of the screw 50.

  In this example, the front ramp 14 has a transverse string of a plurality of three facets 15, 16, 17, tangent to a fictitious conical surface having the shape of the conical portion 54, in order to have as many generators sliding contact, to limit wear. The generatrices above, however, are functionally replaced by surfaces if each facet 15, 16, 17 has a curvature corresponding to that of the conical portion 54. The rosary above forms a sort of triptych, the side facets 15 and 17 being slightly folded towards each other to form, with the central facet 16, a widely open cavity with flared U-section. The lateral facets 15 and 17 further ensure, with the clearance in the guide hole 35, a centering of the wafer 10 with respect to the screw 50 and thus with respect to the axis 51, then common to the guide hole 35 and to the screw 50.

  Whatever the single or multiple embodiment of the front ramp 14, it may have a decreasing inclination towards a top zone thereof, that is to say in the area closest to the rear sidewall 5, in order to allow effective final tightening without the user having to exert excessive force.

  However, in this example, the sliding axis 36 is not exactly parallel to the general axis 31, but slightly inclined thereto so that the driving direction of the screw 50 approaches the general axis 31, so that the axial sliding backwards, printed on the plate 10 by the screw 50, is accompanied by a sliding component radial to the general axis 31, that is to say that the sidewall radially inner longitudinal 4 also serve as a flank of plating against the longitudinal side 44 of the housing 40. Thus, the front ramp 14 is at least partially turned away from the junction point of the lower respectively longitudinal and rear edges 24, 25 , and corner ridge 8.

  Alternatively, the above inclination of the sliding axis 36 on the general axis 31 may be of opposite sign, that is to say with the conical portion 54 closer to the general axis 31 than is the guided section 55, in order to overcome the effects of unclamping by centrifugal force.

  Still in a variant, it may be provided that the rear frame flank 5 has a profile, straight or curved, and an extension direction that is not perpendicular to the sliding axis 36, thus enabling it to slide radially substantially towards the rail. general axis 31, that is to say having a wedge effect allowing the plate 10 to slide radially and / or turn on the bottom 41, so that the longitudinal flank 4, or at least one point thereof, It is therefore unnecessary to provide a specific mechanism for generating the radial displacement, since the backside of the frame 45 serves to deviate, radially inwards, the axial thrust provided by the screw 50.

  In the same vein, the rearward framing side 45 may have an extension direction folded less than 90 degrees to the bottom 41, for example at an angle of 70 to 85 degrees, to form a ramp cavity. upper frontal which, by wedge effect, flaps against the bottom 2864799 23 41, the rear zone (5) of the wafer 10, forming a peak-point rostrum 25, which otherwise would be able to vibrate because it n ' is not opposed to the frontal ramp 14, central and therefore does not directly receive the support force. It may be the same for the lateral side 4. It will be noted that, in another example, with a reversible plate 10 capable of being implanted in two possible positions, the rear rostrum edge 25 may be a cutting edge. In such a case, the front ramp 14 may be a groove or it is the bottom 41 which has a groove for the passage of a protuberance carrying the front ramp 14, in relief on the so-called upper face 2, then turned upside down.

  In the latter case, the groove of the bottom 41 may end with a rear abutment surface having the same function as the rear side 45. The above end surface of the groove of the bottom 41 thus receives that two front ramps 14 which is returned under the plate 10 and which faces towards the rear of the milling cutter 30, or receives a lateral extension of this upside-down end ramp 14 which rises towards the plane of the bottom 41 while going backwards. The extension above can thus have any desired inclination, and in particular a reverse inclination of that of the front ramp 14 considered, for example rotated 90 degrees, to form a rostron with a peak edge at the bottom the groove of the bottom 41, rostrum cooperating with a cavity of complementary shape, as has been exposed for the rear edge 25. Similarly, an edge of the groove of the bottom 41 can serve as a sliding guide edge ent or lateral registration of the plate 10.

  The bottom 41 of the housing 40 may alternatively extend in a slightly inclined plane, for example up to 15 degrees, relative to the general axis 31 of the cutter 30. In such a case, it may be provided that another housing 40B, 40C has a bottom 41B, 41C extending in a plane having an inclination, with respect to the general axis 31, in the opposite direction to that of said inclination of the housing 40.

  In this example, the housing 40 is arranged so that the cutting edge 13 of the wafer 10 extends radially to the general axis 31 of the cutter 30, and the other housings 40B, 40C are arranged so that the The associated cutting edge stops at a distance from the general axis 31. It is thus reserved a central partition core separating the housing 40 from the other 40B, 40C, to ensure the strength of the cutter 10.

  FIG. 5 is a top view illustrating a variant, discernable in FIG. 4, in which the front ramp 14 constitutes an upstanding end stop for the conical portion 54 in its backward translational movement along the sliding axis 36, is preceded by a lateral ramp 14A "horizontal" slightly oblique direction of extension, and precisely whose an axially rear portion extends in a passage volume of the cylindrical portion 53, so as to constitute an oblique obstacle to its progression to the rear of the cutter 30, during the screwing of the screw 50.

  The lateral ramp 14A forms a top view, with the direction of extension of the longitudinal sidewall 4, a corner angle A pointing towards the front, that is to say that it is defined in the plate 10, a trapezoidal area 11, or corner, whose base is axially behind. The sliding axis 36 forms, meanwhile, an angle B with the direction of extension of the longitudinal lateral side 44.

  The corner angle A is greater than the angle B, so that, during the translation, towards the rear of the cutter 30, the clamping section 52 along the sliding axis 36, in order to come to the contact of the front ramp 14, the cylindrical portion 53, sliding on the side ramp 14A, spares its axial path by laterally pushing the lateral ramp 14A towards the lateral side 44. The arrow F1, illustrating the trajectory of a current point of contact of the cylindrical part 53 with the lateral ramp 14A, shows that this trajectory is directed towards a basal zone of the trapezium 11, that is to say that it tends to bite into the volume of plate 10 corresponding to the trapezium 11.

  Thus, in a first screwing phase, the cylindrical portion 53, progressing back towards the base zone of the trapezium 11, moves the plate 10 by pushing the lateral ramp 14A towards the lateral side 44, and this without difficulty as long as the longitudinal flank 4 can move back laterally, that is to say it is not yet pressed against the lateral side 44. This latter situation occurs however when the cylindrical portion 53 arrives at an area of the trapezium 11 having a width corresponding to a space remaining free between a current contact point of the cylindrical portion 53 on the side ramp 14A and an area facing the lateral side 44. The wafer 10 then occupies the position evoked by dotted lines, one end rear of the longitudinal flank 4 reaching the point referenced 441.

  We then enter a second phase, in which, during the continuation of the screwing, the lateral ramp 14A no longer deviates from the path of the cylindrical portion 53 and thus exerts on the clamping section 52 a radial force which tends to make it bend. Therefore, the race 2864799 26 of screwing provided for the second phase, between the point 441 and the corner edge 8, is very limited, that is to say that, at the beginning of the second phase, the flank 5 is at a predetermined, relatively low axial end-of-travel distance from the rear registration flank 45. Precisely, the end-of-travel distance (point 441 at corner edge 8) is determined so that, taking into account the the value of the difference between the angles A and B, which determines the wedge effect, and taking into account the cantilever length of the clamping section 52 with respect to the guide hole 35, the bending of the section of clamping 52 remains in a range of elastic deformation and that, in addition, the screwing effort, to be exerted by the user in the second phase, remains limited. The above bending thus deviates the clamping section 52 in a radial component direction, moving it away from the lateral side 44 and, generally, from the general axis 31.

  In this example, and as shown in Figure 4, the lateral ramp 14A is formed in an extra thickness of the upper face 1. More precisely, in this extra thickness has been formed a groove 14R bottom 14F between two sidewalls one of which is the side ramp 14A, opposite a flank, non-functional, which can be omitted, the groove 14R then limiting a single lateral shoulder. The front ramp 14 blocks a rear end of the groove 14R.

  The groove 14R here being of limited depth with respect to a diameter value of the clamping section 52, only a lower sector of the cylindrical portion 53 is in contact with the lateral ramp 14A, so that at the desired component of parallel force at the bottom 41 for the wedge effect by the trapezium 11, is added here a vertical component, bearing on the bottom 41. The bending of the clamping section 52 mentioned above thus also has a "vertical" component, that is to say, the distance from the bottom 41. There is already, during the second phase, a clamping effect against the bottom 41. Note that the side ramp 14A could be limited to a contact generator with the conical portion 54, so that it is clear that does not come into play the inclination, or slope, of the lateral ramp 14A, that is to say the stiffness of the flanks of the groove 14R, by relative to the plane of extension of the upper face 1, thus also in relation to the bottom 41.

  In a third phase, it is the conical portion 54 which intervenes, as explained above, by cooperation with the front ramp 14 closing the rear end of the groove 14R. It then adds a bending component of the clamping section 52 away from the bottom 41.

  In summary, the trajectory of the wafer 10 is such that it first lands very obliquely by gentle repulsion, for example by an angular difference A - B less than 15 degrees, on the lateral side 44 and then slide on during the second phase, which maintains the lateral contact above through the elastic bending of the clamping section 52 providing a return force opposing, in operation, the vibration forces.

  Note that the cylindrical shape of the cylindrical portion 53 is of particular interest in the second phase, to provide a sufficient contact surface to prevent damage during the "hard" contact under pressure on the side ramp 14A, while the first phase has no "hard" contact and one-touch contact is sufficient.

  The cylindrical portion 53 may therefore, in a variant, be omitted, its function being provided by a base portion, of maximum diameter and then situated at the free end, of the conical portion 54. For the second phase, a final section, rear (point 441 at corner edge 8) of the side ramp 14A may have an increased slope relative to the rest of the side ramp 14A, that is to say locally with a corner angle A increased. In this way, in the second phase, it is then the conical portion 54 that would undergo the bending force component opposite the longitudinal sidewall 4, while simultaneously being able to cooperate with the front ramp 14.

  The frontal ramp 14 can therefore be provided in an axially advanced position with respect to the initial description, so that the third phase is started during the second phase, or even at the same time, or even before, if the final slip (point 441 to corner edge 8) of the longitudinal flank 4 on the longitudinal side 44 may have excessive friction which could be overcome only by pressing on the front ramp 14.

  In other words, the surface of the front ramp 14, each generator here perpendicular to the direction of rise, is horizontal, that is to say parallel to the upper face 1, continues, forwards of the cutter 30, by the same surface but which, going forwards, tilts or twists, progressively around the sliding axis 36 to take a desired angle of tilt in order to constitute the lateral ramp 14A. Thus, because of this twisting, the clamping section 52 receives, during its forward movement, a normal reaction force on the surface of the lateral ramp 14A, force (component) initially horizontal, parallel to the bottom 41 , force 2864799 29 will gradually turn upwards, because of twisting progressively transforming the lateral ramp 14A in the front ramp 14, lifting the clamping section 52. As indicated above, such a vertical lifting force already exists at starting since, in this example, the lateral support of the clamping section 52 is effected by a part at the same time lateral and lower thereof and thus doubles as a lower support having the effect of the front ramp 14 .

  In general, so that the conical portion 54 exerts, on the front ramp 14, a thrust force which has a main component parallel to the bottom 41, and this for the slippage of the plate 10 to the side rear 45 is facilitated regardless of the coefficient of friction on the front ramp 14, the direction of the sliding axis 36 is inclined at an angle less than 45 degrees, preferably less than 15 degrees, on the extension plane 41. The horizontal sliding of the plate 10 requires only a horizontal thrust on the front ramp 14 with a sliding of the conical portion 54 on the front ramp 14 which will be even more limited than the difference between the direction of the sliding axis 36 and the extension plane of the bottom 41 will be low. If this difference is zero, the sliding on the front ramp 14 may be zero. The risk of jamming by jamming on the front ramp 14 is therefore limited or zero.

  Note also that the sliding axis 36 is above the rear side 45, that is to say the end or final framing side, during the second phase, the rear side 45 being reached by the plate 10 at an angle of incidence greater than 45 degrees and preferably, as here, greater than 75 degrees, while the longitudinal side 4, which is the first side of framing, during the first phase, is reached at an angle less than 45 degrees, and preferably less than 15 degrees. Such a reduced angle thus limits the risk of seizure.

  With regard to the alignment of the front ramp 14 and the lateral ramp 14A with respect to the sliding axis 36, these two ramps 14, 14A, possibly fused into one, have two respective surfaces which are shifted respectively to the top, so opposite the bottom 41, and opposite the longitudinal flank 4, thereby to provide the two bending directions of the screw 50 indicated above. The local radius of the screw 50 at the points of contact of the conical portion 54 on the ramps 14 and 14A is, of course, subtracted from the two offsets above.

  A mouth portion of the guide hole 35 may be flared in a given direction so that the clamping portion 52 can bend further in that direction. Thus, the overhang of the screw 50 being variable in the direction of bending, one can independently adjust two return pairs respectively vertical and horizontal, or more precisely here oblique, corresponding to the ramps 14 and 14A.

Claims (36)

claims   1. Removable cutting insert (10) comprising fixing means adapted to cooperate with clamping means associated with a cutter (30) in order to press a face (2) of support of the wafer on the bottom (41) of a housing (40) of the milling cutter, characterized in that the fixing means comprise a front ramp (14) of offset, inclined with respect to an extension plane of said support face (2) and turned, at least partially, opposite to a flank (5) for framing the wafer, the front ramp (14) being arranged to deviate, in the direction of the framing flank (5), a thrust force exerted by a slider (50) for clamping mounted on the cutter.   2. cutting insert according to claim 1, wherein the front ramp (14) is substantially planar.   3. Plate according to claim 1, wherein the front ramp (14) is in the form of truncated cone sector.   4. Plate according to one of claims 1 to 3, wherein the front ramp (14) comprises at least two sections (15, 16, 17) operatively in parallel and extending generally in respective mutually inclined planes.   5. The wafer according to one of claims 1 to 4, wherein the front ramp (14) has a decreasing inclination towards a crown area thereof.   6. The wafer of claim 1, wherein the front ramp (14) comprises a coupling rack with the slider.   7. Plate according to one of claims 1 to 6, wherein the front ramp (14) is at least partially turned away from a corner (8) separating two side walls (4, 5).   8. Plate according to one of claims 1 to 7, wherein the frame flank (5) is folded to extend substantially at an acute angle, relative to the bearing face (2), to form a rostrum jamming the plate.   9. Plate according to one of claims 1 to 8, wherein the frame flank (5) extends generally in a direction inclined relative to a direction of transverse extension of the front ramp (14), for, after have come into contact with a lateral side (45) of framing belonging to a housing (40) of the cutter, slip wedge in an oblique direction relative to a thrust direction of the slider (50).   10. Plate according to one of claims 1 to 9, having a curvilinear cutting edge (13) for a lateral attack and end.   11. The plate according to one of claims 1 to 10, wherein an upper face (1) of the wafer (10) comprises a stop (18, 19) antiperte of the slide (50).   12. Plate according to one of claims 1 to 11, wherein the end ramp (14) is located at the end of a shoulder (14F) for guiding a clamping section (52) of the slider (50), which is formed by a lateral flank (14A) extending in an inclined direction (A) relative to a longitudinal flank (4) of the wafer (10), thereby forming a lateral deviation wedge of the wafer.   13. A wafer according to claim 12, wherein, along the shoulder (14F), the lateral flank (14A) is twisted so that a final section thereof forms the front ramp (14).   14. Milling cutter comprising means (35, 50) for clamping, against the bottom (41) of a housing (40), a removable cutting insert (10) with a front ramp (14), according to the one of claims 1 to 13, characterized in that the clamping means comprise means (35, 43) for guiding and holding in position a slider (50) for pushing the front ramp (14) towards a framing side (45) which limits the housing (40) and is arranged to serve as a framing stop of an associated framing flank (5) of the wafer (10).   15. Milling cutter according to claim 14, the guide means comprise a hole (35) for guiding a guided section of the slider (55) associated with a clamping section (52) having a frustoconical head (54) for cooperation with the front ramp (14).   The milling cutter according to claim 15, wherein the guide hole (35) is threaded to further serve as an axial drive means of the slider, in the form of a screw (50).   17. A milling cutter according to claim 16, wherein the frustoconical head (54) is rotatably mounted relative to the guided section (55).   The milling cutter according to claim 15, wherein the guide hole (35) forms an axial position holding cavity of the slider, the recess having a lateral extension for rotatably guiding said guided section (55) and axially enclosing a lateral protuberance. of the latter (55), and said frustoconical head (54) 2864799 34 carries a lateral thread designed to cooperate with a rack carried by the front ramp (14).   19. A milling cutter according to claim 18, wherein the guide hole (35) has laterally an axial slot having a terminal widening of the initial introduction of the guided portion (55) in the holding cavity, the enlargement being located opposite the housing (40) so that the wafer constitutes a shutter closure enlargement.   20. Milling cutter according to one of claims 15 to 19, wherein the guide means comprise a surface (43) for guiding the clamping section (52).   21. Milling cutter according to one of claims 15 to 20, wherein a mouth portion of the guide hole (35) is flared in a given direction.   22. Milling cutter according to one of claims 14 to 21, wherein the guide hole (35) has an extension direction (36) extending in a substantially axial plane and radial with respect to a general axis (31). strawberry.   The milling cutter of claim 22, wherein the extension direction (36) of the guide hole (35) is substantially parallel to the general axis (31) of the milling cutter.   The milling cutter of claim 22, wherein the extension direction (36) of the guide hole (35) is substantially perpendicular to the general axis (31) of the milling cutter.   The milling cutter of claim 22, wherein the extending direction (36) of the guide hole (35) defines a direction of depression of the slider (50) away from the general axis (31) of the milling cutter. .   26. Milling cutter according to one of claims 14 to 25, wherein the housing (40) has a longitudinal lateral side (44), radially internal to a general axis (31) of the cutter, extending substantially in a plan deviating from the general axis (31) when moving axially away from a free end of the cutter.   27. Milling cutter according to one of claims 14 to 26, wherein the bottom (41) of the housing extends in a plane inclined relative to a general axis (31) of the cutter.   28. Milling cutter according to claim 27, comprising another housing (40B, 40C) having a bottom (41B, 41C) extending in a plane having an inclination, with respect to the general axis (31), of opposite direction to that of said inclination of said housing (40).   Milling cutter according to one of Claims 14 to 28,   wherein the housing (40) comprises an abutment stop (18, 19) of the slider (50), the slider (50) having a predetermined length and the abutment (18, 19) having two opposite ends limiting a ramp surface (19) oblique with respect to a direction perpendicular to a direction (51) for guiding the slider (50) defined by the guide means (35, 43), said opposite ends being located, with respect to a running point of abutment the slider (50) on a mouth of the guide hole (35) at distances of respectively less than and equal to a length value of the slider (50).   The milling cutter according to one of claims 14 to 29, wherein the framing side (45) is folded down to extend substantially at an acute angle to the bottom (41) of the housing (40) and thus form a ramp. folding the framing flank (5) towards the bottom (41) of the housing (40).   Milling cutter according to one of Claims 14 to 30,   wherein the registration side (45) extends in a direction oblique to a normal to a sliding direction (51) of the slider (50).   32. Milling cutter according to one of claims 14 to 31, comprising at least three said housings (40, 40B, 40C).   The milling cutter according to claim 32, wherein a first one (40) of the housings is arranged so that a cutting edge (13) of the wafer extends radially to a general axis (31) of the cutter, a second (40B, 40C) housing being disposed so that the associated cutting edge stops at a distance from the general axis (31).   34. Milling cutter according to one of claims 14 to 33 for a plate according to one of claims 12 and 13, milling cutter in which the means (35, 43) for guiding the slide (50) are arranged to define a direction of said guide (36) having, relative to a longitudinal framing side (44) of the housing (40), an angle (B) smaller than said corner angle (A).   35. Milling cutter according to claim 34, equipped with a plate according to one of claims 12 and 13, wherein the means (35, 43) for guiding the slide (50) and the lateral flank (14A) of the shoulder. (14F) are mutually offset so that, in an initial stroke to reach the front ramp (14), the slider (50), by wedge effect on the side flank (14A), pushes, in a first phase, a longitudinal flank (4) of the wafer (10) against the longitudinal scribing side (44), and for the slider (50), in a second phase, continuing its stroke to reach the front ramp (14), exerts a clamping force lateral against the longitudinal side (44).   36. A cutter according to claim 35, wherein the slider (50), the slider guide means (35, 50) (50) and the side flank (14A) are arranged to simultaneously exert a said plow force. lateral clamping and frontal clamping against said framing side (45).