DE102011114693A1 - Mechanical or power-operated clamping device for e.g. clamping workpieces of large dimensions on table to mechanically machine workpieces on milling machine, has device for producing force that is aligned against clamping force - Google Patents

Abstract

The device has a base unit (1), and a movable slide unit (2) in which a device for producing force aligned against clamping force is integrated. The produced force is pneumatically, hydraulically or electromechanically applied. A variable clamping assembly (3) is arranged on the slide at different workpiece geometries. A workpiece (4) is fixed in the assembly. The assembly including a workpiece support, a clamp and a clamping spindle is mounted on a cut surface of a head plate. The spindle is connected with a plunger, a spring element and a tension bolt in one of guide columns.

Description

Field of use:

The invention relates to an adjustment system for a clamping device for clamping and fixing of workpieces to be machined, tools and the like on a machine table.

State of the art:

Clamping devices for the machining of workpieces of large dimensions on milling machines and the like must be able to spatially move the workpiece for optimal distribution of machining allowances. This adjustment or adjustment of up and contact elements and clamping elements after measuring the workpiece position or after cracks on the workpiece are necessary.

The measurement of the workpiece position, after loading the tensioning device outside or partially automated z. B. done by means of buttons in the milling machine. Certain compensation processes can usually be avoided virtually by a, usually axis-parallel, coordinate shift within the milling machine. Beyond these possibilities compensatory movements of the workpiece are usually manually z. B. spindles / threaded bolt o. Ä. Realized and typically take place in the untensioned state of the workpiece.

The actual clamping of the workpiece is typically done manually via mechanical elements.

Also known are adjustable tensioning devices in terms of adjustment to a new workpiece with other geometric properties. Such clamping devices are z. As described in the company publication "Kostyrka-Universal Holding Fixture", but not the object of the invention described herein.

Disadvantages of the prior art:

Disadvantage of the known solutions is the necessary time-consuming operation of the manual adjustment of the clamping device for optimal alignment of the workpiece for mechanical processing. Depending on the structure of the milling machine, repeated insertion and removal and, in each case, a corresponding repeated clamping and releasing of the workpiece in the clamping device become necessary. The adjustment of the workpiece in the released state is necessary because of the resulting during tilting or moving the workpiece friction forces and the change of spans due to the changed workpiece position to avoid unwanted distortion of the workpiece.

Object of the invention:

The object of the invention is to provide a clamping device which eliminates the disadvantages of the aforementioned solutions and allows automated alignment of the workpiece within the clamping device in the tensioned state.

Solution of the task:

The object is achieved by a clamping device with the features of claim 1.

Advantages of the invention:

• • Das Verstellen der Spannvorrichtung kann automatisiert ohne manuellen Eingriff erfolgen.
• • Zum Verstellen wird die Spannkraft der mechanischen Spannung des Werkstücks selbsttätig gesteuert innerhalb der Spannvorrichtung soweit reduziert, dass ein verspannungsfreies Bewegen des Werkstücks möglich ist. Je nach Anwendungsfall und Wirkungsrichtung der Schwerkraft kann die Reduzierung bis zum Lösen des Werkstücks erfolgen.
• • Nach dem Ende des Verstellvorgangs wird die zur Bearbeitung notwendige Höhe der Spannkraft wieder hergestellt.
• • Die Reduzierung und der Wiederaufbau der Spannkraft erfolgen über ein einfaches Federspannsystem mit einer Entlastungseinheit z. B. über ein hydraulisches System.
• • Die Spannkrafterhaltung über ein Federsystem bietet eine selbsttätige Anpassung an, nach dem Verstellen der Spannvorrichtung, geringfügig veränderte Spannweiten sowie einen Nachspanneffekt.
• • Zur Verringerung von Werkstückverspannungen nach der Schruppbearbeitung kann zur Feinbearbeitung des Werkstücks eine Spannkraftreduzierung vorgenommen werden.

The advantages of the invention consist in the following points:

• • The adjustment of the clamping device can be automated without manual intervention.
• • To adjust the clamping force of the mechanical stress of the workpiece is automatically controlled within the clamping device reduced so that a tension-free movement of the workpiece is possible. Depending on the application and the direction of gravity, the reduction can take place until the workpiece is released.
• • After the end of the adjustment process, the necessary amount of clamping force is restored.
• • Reduction and rebuilding of the clamping force are performed by means of a simple spring tensioning system with a relief unit z. B. via a hydraulic system.
• • The clamping force maintenance via a spring system offers an automatic adaptation, after the adjustment of the clamping device, slightly changed spans and a tensioning effect.
• • To reduce workpiece tensions after roughing, a clamping force reduction can be used to finish the workpiece.

Description of exemplary embodiments:

The clamping device - 1 - consists of the basic unit 1 and the carriage unit 2 and the clamping structure 3 , An example is a workpiece 4 clamped in the clamping structure. To the basic unit 1 belong housing 5 , Adjusting drive 6 as well as the guide elements 7 , To the slide unit 2 according to 2 include a headstock 8th as well as 2 guide columns 9 , On the interface 14 the top plate is mounted a clamping structure 3 , in the example consisting of workpiece support 10 , Clamp iron 11 and clamping spindle 12 ,

The clamping spindle 12 is according to 3 with a piston 13 , a spring element 15 and a draw bolt 18 in one of the guide columns 9 connected. The piston can be between a lower ( 16 ) and an upper fixed stop 17 move.

In the untensioned state pulls the spring package 15 the piston 13 on a lower hard stop 16 ,

When clamping and operating the clamping spindle 12 and becomes the piston 13 from the hard stop 16 lifted and by the spring element 15 the clamping force on the clamping iron 11 applied.

For adjusting the carriage unit 2 that will be in the space between pistons 13 and hard stop 16 pressurized fluid. Depending on the size of preload force of the spring element 15 as well as the pressurization of the fluid takes place while reducing the with the clamping spindle 12 generated clamping force on the workpiece 4 , After the end of the pressurization of the fluid builds the spring element 15 the resilience rebuilt.

Claims (5)

Mechanical or power-operated clamping device for clamping and fixing of workpieces or the like, characterized in that a reduction of the force acting on the workpiece clamping force is achieved by initiation of a clamping force opposing force. Clamping device according to claim 1, characterized in that one of the clamping force directed against force is applied pneumatically or hydraulically. Clamping device according to claim 1, characterized in that one of the clamping force directed against force is applied electromechanically. Clamping device according to one of the preceding claims, characterized in that the means for generating the clamping force opposing force is integrated in a movable carriage of the clamping device. Clamping device according to one of the preceding claims, characterized in that on the movable carriage variable clamping structures for adaptation to different workpiece geometries with the means for generating the clamping force opposing force can be constructed.

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