DE20012246U1 - Tool holder with anti-rotation lock - Google Patents

Description

Utility model registration

Tool holder with anti-twisting device Le(}eiüiirc &Ogr;,&tgr;$&rgr;&$-&Iacgr;&zgr;&uacgr;&iacgr;®.

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Description

The invention relates to a tool holder for shaft tools with cylindrical shafts, in particular for machining wood materials or similar materials, which has the features of the preamble of claim 1.

State of the art

The collet chucks adopted from metalworking have an external thread and a conical collet holder at one end, in which the collet, with a conical outer surface and a cylindrical shaft receiving hole, is received and axially clamped with a union nut in such a way that the tool receiving hole is reduced to such an extent that the tool shaft is clamped. The clamping force is determined by the tightening torque with which the union nut is tightened.

In the past, as is common in metalworking, collet chucks and union nuts with right-hand threads were used for right-hand rotating tools and left-hand threads for left-hand rotating tools. This ensured that the cutting forces acted in the direction of the tightening torque and thus increased the clamping force. A force directed in the opposite direction would reduce the tightening torque and ultimately lead to the union nut and thus the tool coming loose. Ultimately, the tool and the union nut would be thrown off the drive spindle.

As with metalworking, woodworking is also carried out on machining centers. When machining a workpiece, a wide variety of tools are used one after the other and are swapped into the drive spindle by an automatic tool changer. In order to achieve high productivity of the machining center, attempts are made to keep the tool change times as short as possible. In practice, this means that today the drive spindles can go from standstill to full speed within 0.5 seconds.

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operating speed or can be brought to a standstill from the operating speed in the same period of time.

In contrast to metalworking, where large-diameter tools are usually used at a speed of around ^3,000 rpm, speeds of 24,000 ^rpm are common in woodworking.

The fact that the deceleration times and the acceleration times are comparable means that the previous solution of direction-dependent collet chucks and union nuts is no longer applicable.

Object of the invention

The object of the invention is therefore to design existing chucks in such a way that loosening of the union nut due to the occurring loosening torques (acceleration/braking ramp) is excluded.

This object is achieved by a tool holder having the features of claim 1.
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In the first embodiment, the tool holder according to the invention can be designed such that a pin is arranged in the union nut, which engages in one of the recesses in the end section and thereby the union nut and the tool holder are positively connected to one another.

One advantage of the tool holder according to the invention is that the union nut can be tightened with a defined torque. The positive fixation of the clamping nut ensures that the selected tightening torque does not change during the acceleration or braking process. This ensures consistent clamping conditions.

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Furthermore, the invention prevents the acceleration or braking process from leading to an increased tightening torque, which would result in the union nut no longer being able to be loosened using the existing wrenches.

It is particularly advantageous that the tool holder according to the invention is based on the known collet chuck and has the same shape and dimensions and can therefore easily replace the existing collet chuck.

The subject matter of the invention is explained below with reference to the embodiments shown in the accompanying drawings

explained.
15

Show it

Fig. 1 a tool holder according to the invention in half section

Fig. 2 the union nut
Fig. 3 the collet holder in half section Fig. 4 another embodiment of the union nut

Figure 1 shows the tool holder (1) with the conical collet holder (2) in which the collet (3) and a tool shaft (12) are located. The end section (4) is provided with an external thread (6) onto which the union nut (5) is screwed. The union nut (5) presses the collet (3) in the axial direction into the conical collet holder (2) and reduces the diameter of the shaft holder bore (8), thereby generating the clamping force. After the union nut (5) has been tightened with the specified tightening torque, the union nut (5) is brought into a position by further tightening in which a fixing element (7), the fixing axis (Z) of which is preferably perpendicular to the

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Tool holder axis (Y) runs, engages in one of the recesses (9) located in the area of the threads of the external thread (6), and thus connects the end section (4) and the union nut (5) in a form-fitting manner. 5

Fig. 2 shows the union nut (b ^y ) in half section. In the area of the internal thread (10), the fixing axis (Z ) runs perpendicular to the ^tool holder axis ( ^�U ) on which a fixing element (7 ) can be moved. The fixing element (7 ⁾ can be a threaded pin provided with a conical tip (11) which engages in the corresponding V-groove-shaped recess (9) shown in Fig. 1 and connects the end section ( ⁴ ) and the union nut (5 ) with one another in a form-fitting ^manner .

Figure 3 shows the tool holder (1 ^λ ) with the end section (4 ^λ ). The threads of the external thread (6 ^λ ) are interrupted by one or more recesses (9'). The recess (9 ^λ ) has the shape of an elongated hole. The width of the recess (9 ^λ ) is preferably selected so that it is only slightly larger than the fitting collar (11 ^λ ) of the corresponding fixing element (7 ^λλ ) shown in Fig. 4. In practice, there are several recesses on the circumference. In the present example, there are 6 recesses (9 ^λ ), each offset by 60°. This arrangement makes it possible to fix the union nut (5 ^λλ ) positively onto the end section (4 ^λ ) after every 1/6 turn. The specified tightening torque can be maintained almost exactly.

Figure 4 shows the union nut (5 ^&Lgr;&iacgr; ) in half section.

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The fixing element (7'') here is a threaded pin which is provided with a cylindrical fitting collar (UM.

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Claims (8)

1. Clamping device, in particular for shaft tools for machining wood materials or similar materials, with a conical collet holder ( 2 ) for receiving a collet ( 3 ), with a conical outer contour and a cylindrical tool holder bore and an end section ( 4 , 4 ') provided with an external thread ( 6 , 6 ') onto which the union nut ( 5 , 5 ', 5 ") is screwed and by means of which the collet ( 3 ) is axially displaceable and whereby the diameter of the shaft holder bore ( 8 ) can be changed and a clamping force can be generated, characterized in that at least one fixing element ( 7 , 7 ') is integrated in the union nut ( 5 , 5 ', 5 "), which engages in a form-fitting manner in a recess ( 9 , 9 ') located in the end section ( 4 , 4 '), wherein the threads of the external thread ( 6 , 6 ') are interrupted by at least one recess ( 9 , 9 '). 2. Clamping device according to 1, characterized in that at least two recesses ( 9 , 9 ') are present on the circumference of the external thread ( 6 , 6 '). 3. Clamping device according to 2, characterized in that the recesses ( 9 , 9 ') are arranged at regular intervals on the circumference of the external thread ( 6 , 6 '). 4. Clamping device according to 2, characterized in that the recesses ( 9 , 9 ') are arranged at irregular intervals on the circumference of the external thread ( 6 , 6 '). 5. Clamping device according to 2, characterized in that the recess ( 9 , 9 ') has the shape of an elongated hole and its central axis extends substantially parallel to the tool holder axis (Y, Y', Y"). 6. Clamping device according to 1, characterized in that the fixing element ( 7 ) is designed as a spring-mounted bolt. 7. Clamping device according to 1, characterized in that the fixing element ( 7 ) is preferably a pin and is mounted in the region of the internal thread ( 10 ) which is located in the union nut ( 5 ) and can be moved essentially perpendicular to the tool center axis (Y, Y', Y"). 8. Clamping device according to 7 or 8, characterized in that the fixing element ( 7 , 7 ') on the side facing the recess ( 9 , 9 ') has a width which is slightly smaller than the width of the recess ( 9 , 9 ').