This invention relates to a guiding device for the rolling means in a basin rolling assembly, compris¬ ing a guide path following the shape of the periphery of the basin and a support element for the rolling means movable on rollers along the guide path.

It is previously known to manufacture downwardly tapering bowls or basins of a circular cross-section, for example, of a stainless steel sheet by rolling the sheet against a female mould. The use of such a rolling method is so far limited to the manufacture of circular objects only because it is in this case easy to guide the movement of the rolling means following the contour of the product along a guide path having the shape of a circle. If, on the other hand, a product should be manufactured in which the radius of the circumference varies, it will be substantially more difficult to guide the movement of the rolling means. The lack of a satisfactory guiding device has so far prevented the manufacture of, for example, washing stand basins having gently curved long sides, more steeply curved short sides and steeply curved corners. The object of this invention is to provide a guiding device for a rolling means which permits the manufacture of bowls or basins of the above described kind. The guiding device according to the invention is characterized in that, opposite a first roller mounted in the support element and abutting against the inside of the guide path, the guiding device is provided with a guide means for the support element in which are mounted, one after the other in the direction of the

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path of movement of the support element, a second and third roller, which abut against the outside of the guide path on both sides of the first roller in said direction of the path of movement, and which guide means thus keeps the support element in a predetermined position with respect to the connecting line between the second and third roller, and that the guiding device moreover is provided with a resilient member which presses,- on one hand, the support element out- wards transversally of the guide path and, on the other hand, the guide means inwards transversally of the guide path. The support elementof the rolling means remains always in a radial position and stationary in the radial direction with respect to the guide path, on one hand, by means of the guide means of the support element which, under the action of its two rollers, al¬ ways turns the support element in parallel with the radius of the curve and, on the other hand, by means of the resilient member under the action of which the first roller always remains tightly against the inside of the guide path. This construction gives the guiding device a good stability in the longitudinal direction of the guide path and, nevertheless, it resiliently turns the support element in parallel with the radius at each point of the guide path, due to which the rolling means continuously follows a circumference of the same shape.

The guide means of the support element preferab¬ ly comprises a U-shaped jaw surrounding the support element from three sides. The second and third roller are in this case mounted at the ends of the shanks of the jaw, and the inner surfaces of the shanks are slideable in the transversal direction of the guide

path along guide surfaces of the support element. By means of the jaw, the second and third roller can be positioned at a suitable distance from each other in the longitudinal direction of the guide path and the position of the support element can be adjusted by means of the shanks of the jaw.

The resilient member can preferably be realiz¬ ed, for example, by providing the support element with a rod which penetrates the central part of the jaw, and by providing a compression spring between the end of the rod and the central part of the jaw.

With respect to the stability of the guiding device, it is preferred that the second and third roller are located on different sides of a radius of the guide path drawn through the first roller and at the same distance from this radius.

One preferred embodiment of the guiding device according to the invention will be described in more detail in the following with reference to the accom- panying drawing, in which

Figure 1 shows a guiding device according to the invention as seen in the direction of the guide path, and

Figure 2 is a top view of the guiding device. The Figures show only the parts that are essen¬ tial with respect to the understanding of the inven¬ tion. Of the rolling assembly can be seen in Figure 1 a female mould 1 • on top of which a metal sheet 2 is placed of which a basin is to be rolled. The metal sheet is clamped in place by means of a vertically movable frame plate 3 which, at the mould, is provided with an opening through which a rolling means 4 can get into engagement with the sheet 2. The rolling means

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comprises a small wheel secured to a slide 5 movable in parallel with the inner surface of the mould.

On the upper surface of the frame plate 3 is fastened a guide path 6 of the guiding device of the rolling means 4. Said path has a substantially rectangu¬ lar cross-section, with one of the short sides abutting against the frame plate. The guide path runs around the opening in the frame plate 3 and the recess of the mould, and the inside of the guide path exactly corres- ponds to the shape of the circumference of the mould recess although on a larger scale.

On the guide path 6 is mounted a support element 7 for the rolling means which has the shape of an in¬ verted U and is elongated in the transversal direction of the path. Said element abuts against the guide path and the frame plate 3 by means of rollers, and the slide 5 is mounted on the inside thereof. In order to keep the support element in a vertical position above the guide path and the frame plate, one support roller 8 and 9, respectively, is mounted on each of its wide sides, said rollers running on the upper surface of the guide path. In order to balance the torsioπal force produced by the rolling means, a roller 10 running along the upper surface of a groove 11 in the lateral surface of the guide path is mounted on the inner surface of the support element, and the outer end of the support —e-ementr-±s—p ov±ded—wi h a roller 12 running along the upper surface of the frame plate 3.

It is essentially important with respect to the operation of the rolling means that the support element exactly follows the inner surface of the guide path as seen in the transversal direction of the guide path and that the support element, in the curves of the guide

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path, turns so as to always be parallel with the radius of each curve concerned. In order to reach this object, the rollers running along the inside and outside of the guide path are arranged in the following manner. In the front part of the support element is rigidly mounted a roller 13 which runs along the inner surface of the guide path and which is located in the vertical centre plane of the support element. Opposite the roller 13, on the outside of the guide path, are arranged two rollers 14 and 15 which thus run one after the other along the outer surface of the guide path. The rollers 14, 15 are located at a distance from each other approximately corresponding to the width of the support element on both sides of the support element so that they are located on different sides of a radius of the guide path drawn through the roller 13, preferably at the same distance from this radius. The rollers 14, 15 are rigidly mounted at the end of shanks 17 and 18 of a U-shaped jaw 16. This jaw is positioned so that it surrounds the support element from three sides whereby its central part 19, at the outside of the support element, in general is spaced apart from this element. The inner surfaces of the shanks of the jaw 16 are in sliding engagement with corresponding lateral surfaces of the support element. To said late¬ ral surfaces are fastened guides 20 by means of which the jaw is rovable only in the direction of the plane of the frame plate 3.

In order to press the rollers 13, 14 and 15 tightly against the inside and the outside, respective¬ ly, of the guide path 6, an outwards extending rod 21 is secured to the outer part of the support element and

located in the vertical centre plane of the support element. Said rod passes through a hole in the central - part 19 of the jaw and it is surrounded by a compres¬ sion spring 23 situated between the outer surface of the central part 19 and a stop 22 at the end of the rod. This spring presses, on one hand, the jaw 16 and thereby also the rollers 14, 15 against the outside of the guide path and, on the other hand, the support element 7 outwards whereby the roller 13 is pressed against the inside of the guide path.

The guiding device according to the invention operates in the following manner. As the support ele¬ ment passes along the guide path following the circum¬ ference of the mould recess, the rolling means 4 works the metal sheet 2 so that the part of the sheet at the mould recess sinks towards the bottom of the recess. The rolling means is lowered downwards by means of a driving means (not shown) associated with the slide 5. While following the outside of the guide path the rollers 14, 15 assume a relative position required by each curve. Because the rollers are rigidly mounted in the jaw 16, also the jaw turns along with the rollers. The jaw, in turn, under the action of the inner sur¬ faces of its shanks, turns the support element into a corresponding position. Due to this, the centre line of the support element always assumes a radial direc¬ tion. As stated above, the jaw 16 is radially mova le with respect to the support element, which is necessary as the support element moves from one curve to another. The rollers mounted in the support element and the jaw are preferably ball bearings. The spring 23 may, if desired, be replaced with a hydraulic device, and the member producing the compressive effect may be re¬ placed with a tension device inserted between the out- side of the support element and the inner surface of the central part 19 of the jaw.