DRAWBENCH

Abstract

A draw bench has a draw bed (1), with a die block (2) defining a draw axis (11), with a draw carriage (3) movable along the draw bed (1) and aligned with respect to the draw axis (11), and with at least two racks (5) arranged fixedly on the draw bed (1) and extending in the direction of the draw axis (11), which racks mesh with drivable drive gears (7, 8) provided in the draw carriage (3). The toothing (6) of the racks (5) are provided on sides of the racks (5) facing towards or away from each other, the line of action of the resulting tangential components (Ft) of the tooth forces (F) coincides with the draw axis (11) and the torques caused by the radial components (Fr) of the tooth forces (F) in the region of the two racks (5) and acting on the draw carriage (3) in opposite directions cancel each other out.

Claims

1. A draw bench comprising: a draw bed with a die block defining a draw axis; a draw carriage movable along the draw bed and aligned with respect to the draw axis, and having at least two racks arranged in a fixed position on the draw bed and extending in a direction of the draw axis; wherein the racks mesh with drivable drive gears provided in the draw carriage; wherein the racks have toothing provided on sides of the racks that face towards or away from each other; wherein tooth forces are formed by the drive gears engaged with the toothing, and a line of action of tangential components of the tooth forces coincides with the draw axis; and wherein torques caused by radial components of the tooth forces in a region of the two racks and acting on the draw carriage in opposite directions cancel each other out.

2. The draw bench according to claim 1, wherein the racks each mesh with two of the drivable drive gears mounted in the draw carriage.

3. The draw bench according to claim 1, wherein the drive gears can are each be driven by a gear motor.

4. The draw bench according to claim 1, wherein the racks are arranged in a plane inclined about the draw axis.

5. The draw bench according to claim 2, wherein the drive gears are each be driven by a gear motor.

6. The draw bench according to claim 5, wherein the racks are arranged in a plane inclined about the draw axis.

7. The draw bench according to claim 2, wherein the racks are arranged in a plane inclined about the draw axis.

8. The draw bench according to claim 3, wherein the racks are arranged in a plane inclined about the draw axis.

Description

BRIEF DESCRIPTION OF THE INVENTION

[0009] In the drawing, the object of the invention is shown, for example. It shows

[0010] FIG. 1 a draw bench according to the invention in a simplified plan view,

[0011] FIG. 2 a sectional view of this draw bench according to line II-II of FIG. 1 on a larger scale,

[0012] FIG. 3 a section according to line III-III of FIG. 2,

[0013] FIG. 4 a representation of a design variant corresponding to FIG. 3 and

[0014] FIG. 5 a representation of a further design variant corresponding to FIG. 2.

WAYS OF CARRYING OUT THE INVENTION

[0015] A draw bench according to the invention has a draw bed 1 with a die block 2 for corresponding draw tools and a draw carriage 3, which can be moved along the draw bed 1 on guides 4. To drive the draw carriage 3, a rack drive is provided with two racks 5 arranged in a fixed position on the draw bed 1 and usually composed of individual rack sections, which form a toothing 6 on their sides facing each other or facing away from each other. Drive gears 7, 8 mesh with the toothing 6 of the two toothed racks 5, which are rotatably mounted in the draw carriage 3 and preferably driven individually via a geared motor 9, so that the draw material 10 gripped by the draw carriage 3 can be drawn through the draw tool inserted in the die block 2. The die block 2 specifies the draw axis 11 for the draw tools used, whereby for a multi-strand draw bench the arrangement of the draw tools for the individual strands is selected so that the resulting draw force from the draw forces for the individual draw tools coincides with the draw axis 11 specified by the die block 2.

[0016] As can be seen from FIG. 3, the tooth force F acting on the teeth of the drive gears 7, 8 in the direction of the line of engagement of the teeth of the drive gears 7, 8 and the toothing 6 of the racks 5 can be broken down into a tangential component F.sub.t and a radial component F.sub.r perpendicular to it, which makes no contribution to providing the necessary draw force. The tangential components F.sub.t acting in the longitudinal direction of the racks 5, in conjunction with the pull-through resistance of the drawn material 10 acting in the direction of the draw axis 11, cause load-related torques on the draw carriage 3, which should cancel each other out. For this reason, the arrangement is such that the line of action of the resulting tangential components F.sub.t of the tooth forces F coincides with the draw axis 11.

[0017] If the drive gears 7, 8 are symmetrically opposite each other with respect to the draw axis 11, the torques on the draw carriage 3 caused by the tangential components F.sub.t of the tooth forces F cancel each other out, provided that the matching drive gears 7, 8 are driven with the same torques. In the case of unequal torques and thus unequal tangential components F.sub.t of the tooth forces F in the area of the two racks 5, the line of action of the resulting tangential components F.sub.t shifts out of the center between the two racks 5 in inverse proportion to the ratio of the sums of the tangential components F.sub.t acting on the two racks 5, which means that in such a case the draw axis 11 cannot run symmetrically to the two racks 5.

[0018] The same applies to the torques caused by the radial components F.sub.r of the tooth forces F. With the symmetrical arrangement of the drive gears 7, 8 in relation to the draw axis 11 as shown in FIG. 3, it is obvious that the torques on the draw carriage 3 caused by the radial components F.sub.r cancel each other out. If the drive gears 7 have a different mutual distance compared to the drive gears 8, as indicated in FIG. 4, the drive gears 7, 8 must be arranged symmetrically in relation to a plane of symmetry perpendicular to the draw axis 11 under otherwise identical drive conditions. Such a staggered arrangement of the drive gears 7, 8 of the two racks 5 can be advantageous, for example, with regard to the available space. If the toothing 6 of the racks 5 is not provided on the sides of the racks 5 facing each other, but on the sides facing away from each other, as shown in FIG. 4, other spacing ratios for the drive gears can be maintained, but there are no fundamental changes with regard to torque compensation, because the torques resulting from the radial components F.sub.r of the tooth forces F in the area of one rack 5 cancel each other out with the torques of the radial components F.sub.r of the tooth forces F in the area of the opposite rack 5.

[0019] This also applies to an arrangement as shown in FIG. 5, in which the racks 5 are arranged in a plane 12 that is inclined relative to a horizontal plane about the draw axis 11. This arrangement, which results in a different height position of the racks 5, can be helpful for the lateral discharge of the draw material 10 from the draw bench.