FR2850306A1 - Chuck for holding machined part comprises body carrying return hook taking support on surface of part's protuberance to exert return force towards movable stop on body - Google Patents

Chuck for holding machined part comprises body carrying return hook taking support on surface of part's protuberance to exert return force towards movable stop on body Download PDF

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Publication number
FR2850306A1
FR2850306A1 FR0300965A FR0300965A FR2850306A1 FR 2850306 A1 FR2850306 A1 FR 2850306A1 FR 0300965 A FR0300965 A FR 0300965A FR 0300965 A FR0300965 A FR 0300965A FR 2850306 A1 FR2850306 A1 FR 2850306A1
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FR
France
Prior art keywords
return
means
surface
branch
sliding
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
FR0300965A
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French (fr)
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FR2850306B1 (en
Inventor
Jacques Barbieux
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sandvik Tobler SA
Original Assignee
Sandvik Tobler SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sandvik Tobler SA filed Critical Sandvik Tobler SA
Priority to FR0300965A priority Critical patent/FR2850306B1/en
Publication of FR2850306A1 publication Critical patent/FR2850306A1/en
Application granted granted Critical
Publication of FR2850306B1 publication Critical patent/FR2850306B1/en
Application status is Expired - Fee Related legal-status Critical
Anticipated expiration legal-status Critical

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23BTURNING; BORING
    • B23B31/00Chucks; Expansion mandrels; Adaptations thereof for remote control
    • B23B31/02Chucks
    • B23B31/10Chucks characterised by the retaining or gripping devices or their immediate operating means
    • B23B31/12Chucks with simultaneously-acting jaws, whether or not also individually adjustable
    • B23B31/18Chucks with simultaneously-acting jaws, whether or not also individually adjustable pivotally movable in planes containing the axis of the chuck
    • B23B31/185Chucks with simultaneously-acting jaws, whether or not also individually adjustable pivotally movable in planes containing the axis of the chuck moving first parallel to the axis then pivotally in planes containing the axis of the chuck

Abstract

The chuck for holding a part to be machined (60) comprises a body (1) carrying a return hook (20,29) for the part arranged to take support on a surface (62) of the part's protuberance (61), in order to exert a return force towards a stop (30). The stop is movable on the body so as to exert a reaction support force on a counter support surface (63) of the protuberance turned opposite the support surface.

Description

The present invention relates to a holding mandrel

  of a workpiece in a determined position relative to a machining tool.

  Machining a workpiece requires maintaining it in a precise position relative to the cutting tool. Conventionally, the part, for example machined in a lathe, is held along an axis determined by radial clamping of the jaws of a mandrel, which can each have a front shoulder for the reference of the axial stop of the part. In the case, for example, of a piston for a large displacement, this has the shape of a hollow cylinder partially closed, at the end opposite to the useful surface, by a rib or radial cloth. This fabric constitutes a radial relief which makes it possible to keep the part in abseiling on the shoulders by means of a hook introduced into the piston.

  However, the fact of pulling axially on the fabric, therefore perpendicular to its plane of extension, causes it to flex, which thus transforms the axial traction into radial forces of attraction of the cylindrical wall, thus pushing its external surface to machined. Even if the machining is carried out with precision, the subsequent loosening of the piston by the hook will allow the canvas to return to its radial plane of rest, and the external diameter of the machined piston then "recovers" the initial depression.

  One could think of limiting the axial traction force of the hook, but the piston would be insufficiently held in place, especially when the machining is carried out under high stress, that is to say with rapid advance of the tool. to maintain a high production rate.

  One could also think of increasing the inertia to the bending of the canvas or other hooking relief, but the weighting resulting from the part would generally be

unacceptable.

  The present invention aims to propose a solution to avoid deformation of the hooking relief as a recall of the part.

  To this end, the invention relates to a mandrel for holding a workpiece in a determined position relative to a machining tool, the mandrel comprising a body carrying means for returning the workpiece arranged to bear on a surface of a protuberance of the workpiece, in order to exert a force therein having a return component towards stop means, characterized in that the stop means are mounted movably on the body and arranged to exert a force of counter-support on a counter-bearing surface of the protuberance turned substantially opposite to the bearing surface.

  Thus, the return means and the stop means 20 constitute a clamp which blocks the part against any displacement in the direction of the pinching, so that it is useless to try to pull excessively on the protuberance to return the part to the stop, since the support means come to receive it, moving towards it to pinch it. The initial contact with the part can be established by the return means or by the stop means.

  Advantageously, the return means and the stop means are controlled by common operating means. The order is thus facilitated.

  In such a case, the return means are advantageously coupled to the counter-support means by a movement reversing mechanism belonging to the operating means and the return means and the stop means are preferably arranged to slide in the body according to a movement. relative shear.

  Thus, the return means and the abutment means slide substantially parallel and it is therefore easy to provide that the sliding takes place in a direction free from obstacles, for example axial, which therefore limits the radial extension of the operating volume. and thus allows access to protrusions which are difficult to access.

  In a preferred embodiment, the abutment means comprise a chain of mutually abutting segments to slide together, on a curved track of deflection of a direction of return movement of the operating means, by driving a segment d control end coupled to drive means, belonging to the operating means, also coupled to the return means.

  The curved track thus transforms the return movement, at the level of the control end segment, into a movement of substantially opposite direction at the level of the opposite free end, cooperating with the abutment surface.

  In this case, advantageously, the drive means comprise a wedge for spacing a slot, open opposite to the return direction, limited by two lateral bearing surfaces belonging, respectively, to a sliding branch return, one free end of which carries an anterior hook for returning the workpiece, and to one end face of the control segment, the drive means comprising a return relief from the corner towards the bottom of the slot, in order to push the sliding control segment sideways on the track.

  The corner thus constitutes a functional extension of the track, since it also deflects the direction of the return movement towards the opposite direction, coming into abutment.

  In particular then, the drive means are preferably arranged to return the return branch by a longitudinal translation of the wedge, kept coupled, 10 on said bearing surface of the return branch, by longitudinal guide means, and arranged so that, when the return movement of the branch is blocked by the hooked part which comes to bear on fixed abutment means of the mandrel, the wedge continues its return movement 15 by sliding on said support surface so move in a deflected direction, in order to maneuver the control segment by lateral pushing of the bearing surface thereof.

  It is therefore useless, in order to know the recalled position of the part, to provide a measurement of the position of the movable stop means since the fixed stop means determine this position. In addition, the attachment relief is not subjected to excessive restoring stress, since, as soon as the part comes into abutment, the work of the restoring force exerted by the drive means is deflected, that is to say - Say "commute" to be exerted only on the counter-support segments, thanks to the cooperation with the support surface of the return branch, which deflects, towards the segments, the direction of the return force.

  In another embodiment, the return means comprise a sliding return branch, one free end of which carries a front hook for returning the part, and an intermediate section of which has a relief turned at least partially towards the return direction for , by a wedge effect, slide back the control segment.

  It is therefore the return branch which directly controls the counter-support segments.

  In another embodiment, the return means are coupled to the counter-pressing means by a movement reversing lever belonging to the operating means.

  The invention will be better understood with the aid of the following description of a preferred embodiment of the mandrel according to the invention, with reference to the appended drawing, in which FIGS. 1 and 2 are schematic side views of the mandrel. the invention, respectively in the open and closed position.

  The reference 1 in FIGS. 1 and 2 designates the body of a mandrel, of axis 10, comprising a work holding device, shown here in engagement with a hollow piston to be machined 60, partially closed by a membrane or radial cloth. 61 at its end facing the mandrel body 1. The fabric 61 has a central opening allowing a hook 29 to return towards the body 1, 25 to access its internal surface 62.

  The holding device comprises two branches or kinematic chains whose free ends, intended to pinch the fabric 61, have kinematics with opposite movements. In practice, in order to maintain a symmetry of the forces applied with respect to the axis 10, the holding device is mounted in two copies in the mandrel, only one of the two copies being drawn.

  Such a first branch is constituted by a sliding return branch 20, carrying the return hook 29 at its free end. The branch 20 has a base part 21, intended to be pushed axially towards the piston 60 in order to engage the head hook 29 therein. An intermediate section of the branch 20 has, on the side opposite the axis 10, a lateral cavity limited by a surface 22 inclined on the axis 10, a longitudinal bottom 23 and an opposite shoulder 24 facing the base part 21, 10 that is to say rearward. Another intermediate section, between the cavity 22 to 24 and the hook 29, has, on the side of the axis 10, an axial cavity 26, with an anterior edge 27 inclined on the axis 10, for receiving a fixed stud 6 radial spacing of the branch 20.

  The second branch consists here of a chain of segments 31, 32, 33, that is to say of elements of limited length arranged in abutment end to end to translate together by sliding on a curved guide track 40 of the body 1. The segment 31, posterior, is guided substantially radially and it has a so-called anterior sliding end surface 312, turned about 45 degrees forward, in contact with a posterior sliding end surface 321 segment 32, intermediate, segment 32 which for its part extends substantially parallel to the axis 10. The segment 33, at the head, has an extension direction slightly folded towards the axis 10 so that a tab or back-up pad 39, at the anterior end of segment 33, comes to bear on an outer surface area 63 of the fabric 61 located substantially axially opposite the area of the inner surface 62 on which the hook is supported 29.

  The two branches 20 and 30 are here controlled by a single mechanism comprising an axial pull tab 2, an anterior section of which, here masked by the branch 20, carries a transverse lug 3 for the return control and for the control of the counter-support. The lug 3 is here a stud, of rectangular cross section and with two faces, anterior and posterior, perpendicular to the axis 10. The stud 3 is housed in a housing 5 of the body 1 which is limited by a longitudinal surface 51 and , opposite, by the cavity 22 to 10 24 and here by a section 25 of the branch 20 located beyond the shoulder 24.

  The segment 31, controlling the other segments 32, 33, comprises, at its free end, an inclined surface 311 forming a cam for receiving a movable roller 4, here of circular cross section, housed in the housing 5 on the side of the rear face of the return lug 3. The roller 4 constitutes a wedge having successively two functions during the return movement, described below.

  The longitudinal surface 51, opposite the cavity 22 to 24, 20 provides axial guidance of the roller 4 in order to keep it partially coupled in the cavity 22 to 24, that is to say to guide it in abutment towards the rear surface 22 when it is returned axially by the lug 3. The radial distance separating the surface 51 from the radially external surface of the foot part 21 limited by the cavity 22 to 24 is therefore less than the diameter of the roller 4.

  The reference 7 designates a ring of radial clamping jaws of the piston 60, therefore of centering on the axis 10, drawn sketched. The jaws 7 comprise in this example 30 a frontal axial abutment surface, that is to say that they each have an axial position reference shoulder.

  The operation of the device will now be explained in detail.

  To introduce the hook 29 into the piston 60, held by the jaws 7, through the central orifice of the fabric 61, 5 the branch 20 is first pushed axially by the axial control pull mechanism 2, and precisely by advance of the stud 3, the end closest to the axis 10, engaged in the cavity 22 to 24, axially pushes the front shoulder 24. In the corresponding advanced position 10 (FIG. 1), the axial cavity 26 is located axially at the level of the fixed stud 6, which is therefore housed there, so that the hook 29 can be folded down towards the axis 10 by hand or by an axial return spring, not drawn, acting at any point of the branch 20. 15 Alternatively or additionally, the hook 29 can be in the form of a frustoconical end-piece, the radially outer surface of which forms a cam inclined on the axis 10 in order to slide on the edge of the central passage of the canvas 61 during its advance and thus to recall the hook 20 29 towards the axis 1 0.

  The retraction or axial return of the branch 20, to pass from the position of FIG. 1 to the locking position of FIG. 2, is carried out by the pull tab 2 through the lug 3. The retraction of the lug 3 repels behind the roller 4, which in turn pushes back the branch 20 by pressing on the rear surface 22 of the lateral cavity, which then serves as a shoulder, its inclination not playing. The inclined edge 27 slides on the fixed stud 6 which, by wedge effect, pushes the hook 29 radially up to a distance corresponding to that of the internal surface 62 of the fabric 61.

  When the hook 29 comes to bear on the internal surface 62 of the fabric 61, its recoil movement is blocked by the fact that the piston 60 is already bearing on the fixed shoulders of the front abutment of the jaws 7, or 5 possibly that the piston 60 has been pushed back there by the action of the hook 29. In this position, the roller 4 is also supported on the inclined face 311 of the segment 31. The continuation of the retraction of the lug 3, approaching the rear surface 22 of the cavity 22 to 24, pushes the roller 4 laterally by wedge effect between these two support elements 3, 22, that is to say widens the V-shaped slot by pushing the surface laterally command 311. The housing 5 has, at least at this level, the desired width to allow lateral deviation of the path of the roller 4 relative to the axial return direction 10. All of the segments 30 thus slide on the track 40 until the counter-support tab 39 comes into contact with the zone provided for on the external surface 63 of the fabric 61. The fabric 61 is thus pinched in two zones of 20 substantially axially opposite surface, therefore without significant torsion which would risk deforming it as well as the peripheral surface to be machined of the piston 60.

  A force-amplifying effect can be obtained if desired, by providing an "acute" wedge effect, that is to say with the surfaces 22 and 331 slightly inclined on the axis 10, so that the work of the displacement force of the lug 3 with the roller 4 is transformed into a work of substantially the same value, but of lateral repulsion of the segment 31, with a more reduced displacement, therefore a force 30 increased in proportion.

  It will be noted that the inclinations of the surfaces 22 and 311 of the V-shaped slot and the circular shape of the roller 4 are preferred shapes, which are not compulsory. The roller 4 could indeed have an angular wedge shape, and the obliquity of the surfaces 22 and 311 would only serve to distribute the contact pressure and thus limit wear and the risk of blocking.

  In this example, it is therefore the presence of the shoulder of the jaws 7 which, by the effect of the fixed axial stop when the piston 60 returns, causes the movement of the segments 30 to be triggered, via the 10 inclined surface 22. As a variant, the shoulder portion of the jaws 7 could be omitted, that is to say that, after the introduction of the hook 29 in the piston 60 and its radial deployment for hooking the fabric 61, the branch 30 would be advanced to close the clamp 29, 39, the branch 15 retreating as explained, or being held fixed if controls other than those described here are provided, that is to say separated for the two branches 20, 30.

  As a variant, the branch 20 is integral with the pull tab 2 and has a lateral relief, such as a straight or oblique shoulder (24) 20 of a cavity or else a projection, coming directly into engagement with the cam surface 311 of the control segment 31 or equivalent.

  In the absence of shoulder of the jaws 7, it can be provided that it is the counter-support branch 30 which is first advanced and which controls the retraction of the return branch 20, according to the principles of the mechanisms here. exposed for the same type of command by the recall branch 20.

  Generally, the movement of any one of the two branches 20, 30 controls an opposite movement of the other.

  In general, the branch 30 may consist of any stack of a chain of substantially incompressible elements. One can in particular think of a helical spring with contiguous turns, whose flexibility in bending allows easy guidance on the curved track 40, then rounded.

  In another variant, the single control mechanism of the two branches 20, 30 is produced in the form of a reversing lever system with a fixed intermediate axis, replacing the above system, reversing direction of movement, with roller 4 and slot surfaces 22, 311. An arm 10 of the lever, for pivoting control, is coupled to a lateral relief of the branch 20 so as to be driven behind and thus advance an opposite lever arm driving the branch 30 forward. branch 30 can therefore then be straight, the two cooperating branches having the shearing movement, by sliding one in front of the other in opposite directions, as explained in detail.

  Still alternatively, the functional surfaces of the hook 29 and of the counter-support tab 39 are inclined on the axis 10 to clamp a fabric 61 or equivalent with extension in a non-radial plane. The clamping device can therefore ensure blocking in any direction and it can even be provided that it comprises several pairs of branches to block the workpiece in at least two directions. In pairs of pliers holding 25 for example a conical fabric can thus maintain a part in axial and radial position.

Claims (9)

claims
  1. Mandrel for holding a workpiece (60) in a determined position relative to a machining tool, the mandrel comprising a body (1) carrying means (20) for returning the workpiece (60) arranged to bear on a surface (62) of a protuberance (61) of the workpiece (60), in order to exert a force therein having a return component towards stop means (30), characterized by the fact 10 that the stop means (30) are mounted mobile on the body (1) and arranged to exert a counter-pressing force on a counter-bearing surface (63) of the protuberance (61) turned substantially opposite to the surface support (62).
  2. Chuck according to claim 1, wherein the return means (20) and the stop means (30) are controlled by common operating means (2, 3, 4).
  3. Chuck according to claim 2, in which the return means (20) are coupled to the counter-pressing means (30) by a movement reversing mechanism (3, 4) belonging to the operating means.
  4. Chuck according to claim 3, in which the return means (20) and the stop means (30) are arranged to slide in the body (1) according to a relative shearing movement.
  5. Chuck according to one of claims 2 to 4, wherein the stop means comprise a chain of segments (31, 32, 33) mutually in abutment for sliding together, on a curved track (40) of deflection of a 30 direction of return movement of the operating means (20), by driving a control end segment (31) coupled to driving means (3, 4), belonging to the operating means, also coupled to return means (22, 24).
  6. Chuck according to claim 5, wherein the drive means comprise a wedge (4) for spacing a slot (22, 311), open opposite the return direction, limited by two surfaces lateral support (22, 311) belonging, respectively, to a sliding return branch (20), one free end of which carries an anterior hook (29) for returning the part (60), and to one end face 10 of the control segment (31), the drive means comprising a relief (3) for returning the corner (4) towards the bottom of the slot (22, 311), in order to push the control segment (31) laterally in sliding on the track (40).
  7. Chuck according to claim 6, wherein the drive means (2, 3, 4) are arranged to return the return branch (20) by a longitudinal translation of the wedge (4), kept coupled, on said surface bearing (22) of the return branch (20), by means of longitudinal guide (51), and arranged so that, when the return movement of the branch (20) is blocked by the hooked part (60 ) coming to bear on fixed abutment means (7) of the mandrel, the wedge (4) continues its return movement by sliding on said bearing surface (22) 25 so as to move in a deflected direction, in order to maneuver the control segment (31) by lateral pushing of the bearing surface (311) thereof.
  8. Chuck according to claim 5, in which the return means comprise a sliding return branch (20), one free end of which carries a front hook (29) for returning the part (60), and one of which has an intermediate section. comprises a relief (24) turned at least partially towards the return direction to, by a wedge effect, push back in sliding the control segment (31).
  9. Mandrel according to claim 2, in which the 5 return means (20) are coupled to the counter-pressing means (30) by a movement reversing lever belonging to the operating means.
FR0300965A 2003-01-29 2003-01-29 Chuck pince Expired - Fee Related FR2850306B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR0300965A FR2850306B1 (en) 2003-01-29 2003-01-29 Chuck pince

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0300965A FR2850306B1 (en) 2003-01-29 2003-01-29 Chuck pince
DE200410004218 DE102004004218A1 (en) 2003-01-29 2004-01-27 Clamp chuck

Publications (2)

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FR2850306A1 true FR2850306A1 (en) 2004-07-30
FR2850306B1 FR2850306B1 (en) 2006-01-20

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FR0300965A Expired - Fee Related FR2850306B1 (en) 2003-01-29 2003-01-29 Chuck pince

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FR (1) FR2850306B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006050472B4 (en) * 2006-10-20 2011-07-21 Männel Werkzeugbau GmbH, 08209 Device for clamping flat workpieces for machining on machine tools
DE102014102082A1 (en) * 2014-02-19 2015-08-20 Ott-Jakob Spanntechnik Gmbh Tool turret

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4902156A (en) * 1987-02-21 1990-02-20 Dipl. Ing. Rudolf Hell Gmbh Mounting device for image cylinders
US6036197A (en) * 1997-09-09 2000-03-14 Sandvik Tobler S.A. Device for clamping and driving a pre-positioned work piece
US6371493B1 (en) * 1999-01-25 2002-04-16 Sandvik Tobler S.A. Adaptive clamping type chuck
US6409182B1 (en) * 1999-05-05 2002-06-25 Rohm Gmbh Lathe chuck with two sets of jaws

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4902156A (en) * 1987-02-21 1990-02-20 Dipl. Ing. Rudolf Hell Gmbh Mounting device for image cylinders
US6036197A (en) * 1997-09-09 2000-03-14 Sandvik Tobler S.A. Device for clamping and driving a pre-positioned work piece
US6371493B1 (en) * 1999-01-25 2002-04-16 Sandvik Tobler S.A. Adaptive clamping type chuck
US6409182B1 (en) * 1999-05-05 2002-06-25 Rohm Gmbh Lathe chuck with two sets of jaws

Also Published As

Publication number Publication date
DE102004004218A1 (en) 2004-08-12
FR2850306B1 (en) 2006-01-20

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