CH454570A

CH454570A - Expandable chuck for machining between centers of hollow parts

Info

Publication number: CH454570A
Application number: CH1081967A
Authority: CH
Inventors: Demierre Claude
Original assignee: Demierre Claude
Priority date: 1967-07-28
Filing date: 1967-07-28
Publication date: 1968-04-15

Description

  

      Mandrin    expansible pour     husinage        entre        pointes    de     pièces    creuses    La présente invention a pour objet un mandrin ex  pansible pour l'usinage entre pointes de pièces creuses,  caractérisé par un plateau centreur pourvu d'un alésage  conique central duquel partent une première série de fen  tes radiales disposées en quinconce par rapport à une  deuxième série de fentes radiales partant de l'extérieur  du plateau et par un cône tronqué dans lequel est prati  qué un centre de pivotement de l'ensemble surmonté  d'une collerette filetée sur laquelle se visse un écrou d'ex  traction du cône tronqué.  



  L'invention a pour but de permettre le tournage entre  pointes de pièces creuses devant être reprises en usinage  concentriquement par rapport à l'alésage primitif.  



  Le dessin annexé représente, à titre d'exemple, une  forme d'exécution de l'objet de l'invention.  



  Le mandrin expansible représenté comprend un pla  teau centreur (1) dans lequel sont pratiquées deux séries  de fentes radiales (2) et     @(3)    arrêtées par des perçages  transversaux (4) et (5). Une portée cylindrique (6) et un  appui axial (7) réalisés sur le diamètre extérieur du pla  teau centreur (1) sont destinés à recevoir la pièce à usiner.  Un cône tronqué (9) logé dans l'alésage conique (8) du  plateau centreur. (1) comporte le centre de pivotement<B>(</B>10)  de l'ensemble, lequel est protégé par une collerette filetée  (11) qui est destinée d'une part à limiter     l'enfoncement     du cône tronqué (9) dans l'alésage (8) et, d'autre part, à  recevoir un écrou (12) d'extraction du cône tronqué (9).  



  La reprise concentrique de la pièce à usiner montée  entre pointes est assurée par l'ajustement de la portée  cylindrique (6) résultant de l'expansion radiale du pla  teau centreur (1). Cette expansion est obtenue par la    poussée de la contre-pointe de la machine-outil sur le  centre de pivotement (10) provoquant l'enfoncement du  cône tronqué     :(9)    dans l'alésage central (8) du plateau  centreur (1) retenu par l'appui axial (7).



      The present invention relates to an expanding mandrel for machining between centers of hollow parts, characterized by a centering plate provided with a central conical bore from which a first series of radial windows start. staggered with respect to a second series of radial slots starting from the outside of the plate and by a truncated cone in which is practiced a pivoting center of the assembly surmounted by a threaded collar on which is screwed a nut of 'ex traction of the truncated cone.



  The object of the invention is to allow the turning between centers of hollow parts which have to be machined again concentrically with respect to the primitive bore.



  The appended drawing represents, by way of example, an embodiment of the object of the invention.



  The expandable mandrel shown comprises a centering plate (1) in which are formed two series of radial slots (2) and @ (3) stopped by transverse bores (4) and (5). A cylindrical bearing surface (6) and an axial support (7) produced on the outside diameter of the centering plate (1) are intended to receive the workpiece. A truncated cone (9) housed in the conical bore (8) of the centering plate. (1) comprises the pivoting center <B> (</B> 10) of the assembly, which is protected by a threaded collar (11) which is intended on the one hand to limit the depression of the truncated cone (9 ) in the bore (8) and, on the other hand, to receive a nut (12) for extracting the truncated cone (9).



  The concentric recovery of the workpiece mounted between centers is ensured by the adjustment of the cylindrical surface (6) resulting from the radial expansion of the centering plate (1). This expansion is obtained by the thrust of the tailstock of the machine tool on the pivoting center (10) causing the depression of the truncated cone: (9) in the central bore (8) of the centering plate (1) retained by the axial support (7).

Claims

CLAIM Expandable mandrel for the machining between centers of hollow parts, characterized by a centering plate provided with a central conical bore from which a first series of radial slots begin, arranged staggered with respect to a second series of radial slots starting from the outside of the centering plate and by a truncated cone provided with a pivoting center surmounted by a threaded glue on which is screwed a nut intended for the extraction of the truncated cone. SUB-CLAIMS 1. Mandrel according to claim, characterized in that each radial slot of the centering plate is stopped by a transverse bore. 2.

Mandrel according to claim, characterized in that the pivoting center of the assembly, produced in the truncated cone, is protected by the threaded collar of the truncated cone. 3. Mandrel according to claim and sub-claim 2, characterized in that the threaded collar limits the insertion of the truncated cone into the bore of the centering plate.