EP0887147B1 - Hydraulic clamp with anti-locking release for clamping tools on press-table - Google Patents

Description

The present invention relates to a device for blocking a tool on a press table.

The devices currently used called flanges to angle or inclined flanges have the disadvantage, in in some cases, to ask, as a result of distortions elastic and molecular packing of tight parts, release efforts greater than those generated by the double-acting actuator. This drawback results also of the moving jaw arch, the guidance of which cannot be sufficient in the space available and which by construction presents an important game rendered required by operation required at temperatures relatively high (200 °). on the other hand, moving linear of this movable jaw, parallel to the support plane the volume to be tightened means that the recoil is not clear and that the jamming effect persists throughout or partially of the stroke if the said volume rubs against the withdrawal movement of the clamping jaw.

The device according to the invention overcomes this disadvantage.

The goal is to obtain non-buttressing guidance of the clamping jaw by increasing the guidance of this jaw (in the space available) to increase the bearing surfaces of the jaw on its guides, finally, to obtain a movement releasing the jaw from the start of loosening while retaining the irreversibility of the system.
This object is achieved by a device according to claim 1.

• De venir brider le volume sous l'action du vérin en position avancée.
• De venir s'escamoter totalement à l'intérieur des guides sous l'action du vérin en position recul.
• La forme en secteur de couronne cylindrique du mors mobile permet à celui-ci d'avoir une trajectoire dégageante dès le début du désserrage sans aucun risque de coincement.
• Cette forme en secteur de couronne cylindrique du mors mobile permet d'augmenter la longueur de guidage de ce mors minimisant le phénomène d'arc boutement.
• La section transversale rectangulaire du mors mobile a pour conséquence des surfaces d'appui de réaction en position serrage importantes autorisant des efforts considérables.
• Selon des modes spécifiques et étudiés l'ensemble vérin, guides, mors mobile sera assemblé par vissage et piétage formant un bloc unique et compact prêt à son utilisation.

The invention is essentially located in the form of a cylindrical crown sector of the movable jaw. The circular sliding of this jaw between 2 guides under the action of a hydraulic cylinder with rectilinear reciprocating movement will allow it to:

• To clamp the volume under the action of the jack in the advanced position.
• To retract completely inside the guides under the action of the cylinder in the retracted position.
• The cylindrical crown sector shape of the movable jaw allows it to have a clearing trajectory from the start of loosening without any risk of jamming.
• This cylindrical crown sector shape of the movable jaw makes it possible to increase the guide length of this jaw minimizing the phenomenon of bracing.
• The rectangular cross section of the movable jaw results in large reaction support surfaces in the clamping position allowing considerable efforts.
• According to specific and studied modes, the actuator, guides and mobile jaw assembly will be assembled by screwing and trampling forming a single, compact block ready for use.

• La planche 1/5 illustre les dispositifs existants bride à coin (Fig.1) brides inclinées (Fig.2) pour une meilleure explication de l'inconvénient actuel.
• La planche 2/5 illustre l'invention en éclaté
• La planche 3/5 illustre le montage et les données mathématiques et techniques définissant l'invention.
• La planche 4/5 illustre le montage des détecteurs de position.
• La planche 5/5 concerne l'illustration pour l'abrégé.

The accompanying drawings illustrate the invention.

• Plate 1/5 illustrates the existing corner flange devices (Fig. 1) inclined flanges (Fig. 2) for a better explanation of the current drawback.
• Plate 2/5 illustrates the invention in exploded form
• Plate 3/5 illustrates the assembly and the mathematical and technical data defining the invention.
• Plate 4/5 illustrates the mounting of the position detectors.
• Plate 5/5 concerns the illustration for the abstract.

• Le mors mobile (3) étant en appui sur la semelle de l'outil nous avons :
  • l'effort de serrage Fs = PXS1Xab Le mors est alors en équilibre entre les forces
  • de commande Fc = variable de O à P X S1
  • de bridage Fs = FcXab
• Les 2 réactions de guidage F1 et F2 appliquées aux points de contacts respectivement A et B affectées des résultantes du frottement et de la force Fc variable.
• La forme en secteur de couronne du mors mobile permet l'éloignement de A et B, augmentation de la longueur de guidage le phénomène d'arc-boutement est minimisé.
• L'angle d'incidence de F1/Fs est choisi à la limite de la reversibilité de façon à ce que Fc étant présent une action supérieure et opposée à Fs (coincement de l'outil supérieur avec outil inférieur à la remontée de la presse) ne puisse provoquer le désserrage.
• FC étant supprimé l'ensemble est pratiquement en équilibre sous l'effet des frottements.
• FC étant inversé le désserrage est effectué sans problème, la réaction d'élasticité opposée à Fs s'annulant immédiatement et ce, éventuellement, par la seule translation horizontale du vérin (5) qui procure immédiatement à l'ensemble le jeu de fonctionnement nécessaire à sa rotation sans contrainte autour de (0).
• A noter que le jeu fonctionnel important comme nous l'avons dit ne provoque aucune réaction d'arc-boulement.
• La section rectangulaire du mors (3) assure une surface d'appui excluant tout grippage. les matériaux et traitements de surface sont appropriés aux efforts considérables exigés.
• La commande, non exclusivement hydraulique, peut être issue de toute autre source pneumatique par exemple.
• Les dimensions et proportions indiquées sur les plans sont susceptibles de toutes variations en fonction des applications.
• Les rapports de force et notamment l'angle α pouvant varier suivant que l'on souhaitera une irréversibilité plus ou moins assurée en fonction des coefficients de frottement des matériaux utilisés.
• Pourront également varier tout en restant conformes à l'esprit de l'invention les dispositions conscructives telles que séparation entre pièce (1) et (2) et attachement du piston (5) au mors (3).
• Dans le cadre d'une plus grande sécurité dans l'exploitation de l'invention les positions avancées ou rétractées du mors mobile (3) seront contrôlées par détecteurs électriques ou électroniques latéraux avec ou sans connecteur (Fig.3).
• Ce contrôle de position pourra également être fait par détecteurs électriques ou électroniques arrière avec ou sans connecteurs (Fig.4)

Detailed description of the invention:

• The movable jaw (3) being supported on the sole of the tool we have:
  • tightening force Fs = PXS1Xa b The bit is then in balance between the forces
  • control Fc = variable from O to PX S1
  • clamping Fs = FcXa b
• The 2 guidance reactions F1 and F2 applied to the contact points A and B respectively affected by the results of friction and the variable force Fc.
• The shape in the crown sector of the movable jaw allows the distance of A and B, increase in the guide length the phenomenon of bracing is minimized.
• The angle of incidence of F1 / Fs is chosen at the limit of the reversibility so that Fc being present a higher action and opposite to Fs (wedging of the upper tool with lower tool when raising the press) cannot cause loosening.
• FC being suppressed the whole is practically in equilibrium under the effect of friction.
• FC being reversed, the loosening is carried out without problem, the elasticity reaction opposite to Fs canceling out immediately and this, possibly, by the only horizontal translation of the jack (5) which immediately gives the assembly the operating clearance necessary for its rotation without constraint around (0).
• Note that the significant functional clearance as we have said does not cause any bow-over reaction.
• The rectangular section of the jaw (3) provides a bearing surface which prevents any seizing. the materials and surface treatments are suitable for the considerable efforts required.
• The control, not exclusively hydraulic, can come from any other pneumatic source for example.
• The dimensions and proportions indicated on the plans are subject to all variations depending on the applications.
• The power ratios and in particular the angle α can vary depending on whether a more or less assured irreversibility is desired as a function of the coefficients of friction of the materials used.
• May also vary while remaining consistent with the spirit of the invention, the constructive arrangements such as separation between part (1) and (2) and attachment of the piston (5) to the jaw (3).
• In the context of greater security in the operation of the invention, the advanced or retracted positions of the movable jaw (3) will be checked by lateral electric or electronic detectors with or without connector (Fig. 3).
• This position control can also be done by rear electrical or electronic sensors with or without connectors (Fig. 4)

By way of nonlimiting example, the device for clamping, object of the invention, will have a general shape right parallelepiped with a length of 190mm, width of 120mm and height of 80mm.

These geometric characteristics correspond to a clamping device capable of retaining an effort of 100 KN.

A movable jaw (3) in the form of a cylindrical sector allowing the circular sliding of this jaw between 2 guides (1) and (2) under the action of a movement cylinder rectilinear alternative (5) and (4).

The rectangular cross section of the jaw (3) increases the bearing surfaces of support.

A movable jaw in the form of a cylindrical sector (3) reducing the H / L ratio (in space available) to reduce the bracing phenomenon.

The present invention is particularly intended for come energetically hold the tools in place on the mechanical and hydraulic press tables of all types for forging operation - stamping - injection - deformation while ensuring a loosening at will of without jamming problem.

Claims (4)

1. Device for clamping a tool on a press table,
   characterised in that
   it consists of a cylinder / piston unit (4, 5) displaceable in horizontal translation, co-operating with a mobile jaw (3) in the form of a cylindrical ring segment with a rectangular cross section trapped between two guides (1, 2), between which it is able to slide so as to push or pull this mobile jaw (3) in order to clamp or unclamp the tool, the mobile jaw (3) enabling the reaction to the clamping force to be distributed on the upper guide (1).
2. Device as claimed in claim 1,
   characterised in that
   it is hydraulically controlled.
3. Device as claimed in claim 1,
   characterised in that
   it has lateral electrical or electronic sensors, enabling the position of the mobile jaw (3) to be controlled.
4. Device as claimed in any one of claims 1 to 3,
   characterised in that
   it has rear electrical or electronic sensors enabling the position of the mobile jaw (3) to be controlled.

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