Internal roller tool for bending a strip into a tube

Abstract

An internal tool for bending a strip passing in a strip-travel direction into a tube has a support juxtaposable with a face of the passing strip, at least two roller holders pivotal on the support about respective offset holder pivot axes generally parallel to the strip-travel direction, and respective rollers carried in the holders and rotatable about respective roller axes generally perpendicular to the respective holder axes.

Description

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is an end view largely in cross section through the system of this invention;

FIG. 2 is a side view partly in axial section through the system of FIG. 1; and

FIG. 3 is a view like FIG. 2 of a variation on the system of this invention.

SPECIFIC DESCRIPTION

FIGS. 1 3 show an internal shaping tool 1. The metal strip 2 to be shaped being shown only in FIG. 1. The metal strip 2 is displaced in a strip-travel direction R and is pressed inward against the tool 1 by unillustrated outer tools as illustrated schematically at 7 in FIG. 1.

To impart the desired shape to the metal strip 2, the internal shaping tool 1 has a support 3 on which in the present case a total of three rollers 4, 5, and 6, namely two side rollers 4 and 5 and a center roller 6, are mounted, pivotal about respective center axes 4A, 5A, and 6A. All three rollers 4, 5, and 6 contact one face 7 of the metal strip 2, here shown already bent into a U- or C-section. Not illustrated on the other side of the metal strip are starter rollers, that are provided on side roller beams in a known manner, and that exert the inward bending force F.

The two side rollers 4 and 5 are not rigidly mounted on the support 3, as is the center roller 6, but instead are pivotal about respective pivot axes 8 and 9 that extend perpendicularly through the axes 4A and 5A and parallel to the strip-travel direction R. As illustrated most clearly in FIG. 1, the two side rollers 4 and 5 are supported in respective roller holders 14 and 15 that pivot symmetrically with respect to a center plane 10 of the common support 3, the axes 8 and 9 symmetrically also flanking this plane 10. Means 11 are provided for synchronizing the pivoting of the side rollers 4 end 5. In the illustrated embodiment, according to one preferred embodiment these means 11 are composed of sector gears 12 and 13 fixed and even formed on the holders 14 and 15. The sector gear 12 and 13 are centered on the respective axes 8 and 9 and mesh with each other.

The means 11 for synchronization ensure symmetrical positioning of the rollers 4 and 5, thereby facilitating a stable shaping process. In particular, twisting of the shaped body, i.e. the metal strip 2 to be shaped, is prevented.

To enable the two side rollers 4 and 5 to be quickly and easily adjusted to a desired pivot angle, a single extensible actuator 16 is present that, for example, is designed as a screw-nut adjusting system. One end of the extensible actuator 16 connected at a pivot 20 to the support 3. The other end of the extensible actuator 16 is likewise connected at a pivot 21 to one of the two roller holders, here to roller holder 14. Actuation of the extensible actuator 16 results in a change in the distance between the pivots 20 and 21, causing the desired pivoting of the roller holder 14, and therefore the side roller 4, about the pivot axis 6. Engagement of the two toothed sector gears 12 and 13 causes this pivot motion to be simultaneously transmitted to the other roller holder 15, and thus to the other side roller 5, so that both side rollers 4 and 5 are symmetrically pivoted with respect to the center plane 10.

The additional roller 6 designed as a center roller is bisected by the center plane 10 and the axis 6A is perpendicular to this plane 10, which here is parallel to the direction R. The roller 6 may be mounted directly on the support 3 or, as shown in FIGS. 2 and 3, may be mounted on a separate, holder 17. The holder 17 may be vertically shiftable on the support 3 by means or a vertical dovetail guide 22.

The center roller 6 is adjustable vertically perpendicular to the shaping direction R. In the case of the illustrated embodiment according to FIG. 2, the adjustment in this direction is made by an appropriately selected spacers 18. The approach according to FIG. 3 instead provides an adjusting element 19, designed as a screw-nut system, that easily allows the center roller 6 to be adjusted.

By use of the proposed embodiment of the internal shaping tool the rollers may be easily and quickly adapted to a change in the geometry of a shaped body, ensuring precise adjustment to the geometric requirements of the shaped body.

Depending on the application, it is also possible to set only a starting position with the pivot adjustment. The rollers then have a certain degree of freedom for optimal free adjustment, that is achievable in particular by gearing as a transmission means that produces a symmetrical adjustment. In other words the rollers 4 and 5 are set at a certain position to begin the tube-forming operation, but once it has started they are allowed to pivot freely, the sector gears 12 and 13 ensuring that they move synchronously.

Claims

1. An internal tool for bending a strip passing in a strip-travel direction into a tube, the tool comprising: a support juxtaposable with a face of the passing strip;at least two roller holders pivotal on the support about respective offset holder pivot axes generally parallel to the strip-travel direction; andrespective rollers carried in the holders and rotatable about respective roller axes generally perpendicular to the respective holder axes.

2. The strip-bending tool defined in claim 1 wherein each of the roller axes perpendicularly intersects the respective holder pivot axis.

3. The strip-bending tool defined in claim 2 wherein the holder pivot axes are substantially parallel to the strip-travel direction.

4. The strip-bending tool defined in claim 1, further comprising means coupling the holders together for synchronous movement about the respective pivot axes.

5. The strip-bending tool defined in claim 4 wherein the means includes respective meshing sector gears centered on the respective pivot axes.

6. The strip-bending tool defined in claim 4 wherein the means includes an extensible and retractile actuator pivoted on one of the holders and on the support.

7. The strip-bending tool defined in claim 1 wherein the rollers include two side rollers symmetrically flanking a central plane substantially parallel to the strip-travel direction and generally bisecting the strip.

8. The strip-bending tool defined in claim 7 wherein the rollers include a middle roller generally lying on the plane and rotatable about an axis generally perpendicular to the plane.

9. The strip-bending tool defined in claim 7, further comprising means for shifting the middle roller in the plane toward and away from the strip.

10. The strip-bonding tool defined in claim 7 wherein the means includes a threaded nut/bolt assembly engaged between the holder of the middle roller and the support.

11. The strip-bending tool defined in claim 7 wherein the means includes a removable spacer between the holder of the middle roller and the support.