EP0109654A1

EP0109654A1 - Method of and device for splitting a metal circle with an asymmetrical splitting wheel

Info

Publication number: EP0109654A1
Application number: EP83111447A
Authority: EP
Inventors: Otto Berg
Original assignee: Ardal og Sunndal Verk AS
Current assignee: Ardal og Sunndal Verk AS
Priority date: 1982-11-17
Filing date: 1983-11-15
Publication date: 1984-05-30

Abstract

For splitting a metal circle, a splitting wheel (2) having an asymmetrical edge (4, 5) causes the metal circle to be pressed to one side. The forces of this side pressure are absorbed by a supporting wheel (3) fitted in the same tool holder (6) as the splitting wheel.

This device simplifies the auxiliary equipment for positioning the circle during splitting, and further saves work and material.

Description

This invention relates to a method of and device for splitting a circle, i.e. a circular piece of metal plate.
Splitting circles by means of a splitting wheel is known technology. The circle is clamped firmly into position on a suitable lathe and caused to rotate around its center axis. If a conventional spinning lathe is used, with a splitting wheel being held in the fork of the tool post, it is possible to split the circle along its circumference, thus forming a v-shaped groove.
In practice, it has proved difficult, when performing a splitting operation of this nature, to maintain constant plate thickness in the split area. This is due, i.a., to imbalance of the forces acting on the cutting edge of the splitting wheel as soon as this deviates from a symmetrical center position. Particularly in the case of so-called deep splitting, i.e. splitting substantially deeper than the thickness of the material, imbalance can arise leading to inclined splitting, uneven material thickness and possibly rupture.
_Proceduresadopted with the aim of overcoming this difficulty involve the clamping of the circle between flanges, performing the splitting in stages, successively reclamping the circle between flanges of smaller diameter.
Another method aimed at overcoming the difficulties involves the use of supporting wheels which prevent the circle from being deflected sideways, and which retain the circle in a fixed position with respect to the splitting wheel.
This invention relates to a method of splitting a circle by means of a splitting wheel, and an arrangement which greatly simplifies the necessary auxiliary equipment for retaining the circle in the right position during the splitting operation.
The basic principle of the invention is that the circle, during splitting is pressed to one side, and that the circle, on this side is supported by a supporting wheel.
To press the circle to one side during splitting, use is made of an asymmetrical splitting wheel, i.e. the cutting angle is different for the two halves of the splitting wheel, in other words the length of the cutting surfaces are different.
The asymmetrical splitting wheel will cause the circle to be pressed to one side because one of the cutting surfaces exerts a greater force than the other. In this manner, the splitting wheel tries, in a natural manner, to cut its way out of the circle.
Asymmetrical splitting can also be achieved by having the splitting wheel supported in a plane which is not parallel with the rotational plane of the circle, so-that the splitting wheel will aim at a predetermined side, and that the supporting wheel placed on the appropriate side causes the splitting to be performed parallel with the surface of the circle.
A supporting wheel so positioned that it runs perpendicularly along one of the surfaces of the circle provides a support which prevents the circle from being deflected by the splitting wheel. A supporting wheel of this kind must be suspended in a system which is firmly fixed to the splitting wheel's suspension. The system must be sufficiently rigid and stable to ensure that the geometrical relationship between the splitting wheel and the supporting wheel be not changed during the splitting operation. The supporting wheel is positioned on that side of the circle from which the splitting wheel tends to move away.
The invention will now be described in more detail with reference to the attached drawings.
Fig 1 depicts a circle in place in a spinning lathe for splitting, whilst fig 2 shows how the splitting wheel operates in the circle.
In the figures, 1 is the circle clamped into position, 2 the splitting wheel and 3 the supporting wheel. 4 and 5 show the different cutting angles of the splitting wheel, whilst 6 is the tool holder, which contains the splitting wheel and the supporting wheel.
The device for splitting a circle by means of a splitting wheel 2 will thus consist of a splitting wheel with an asymmetrical edge 4,5 and further built into the holder 6 for the splitting wheel, there will be a supporting wheel 3 which prevents the circle from becoming deflected, ensuring a constant distribution of thickness in the split area.
The method proposed will result in substantial saving of operation times, and further be simpler to operate than a system with a symmetrical splitting wheel and two supporting wheels. In the case of circles with varying plate thickness, it will be possible to achieve a distribution after splitting resulting in even thickness in one of the wings.
When a system is used involving a symmetrical splitting wheel and two supporting wheels, these have to be freed from one another before the splitting wheel can return to its initial position after splitting. With the method proposed it will be possible to perform such a return movement of the splitting wheel without altering the positions of the splitting wheel and the supporting wheel relative to one another.
Also in the case of so-called asymmetrical splitting, i.e. when the two wings after splitting are of different thickness, the asymmetrical splitting wheel will be applicable. The appropriate cutting angle will have to be chosen in each individual case, so that the forces will be as near as possible to balancing point thus avoiding unnecessary stresses of the workpiece and tool.

Claims

1. A method of splitting a metal circle (1)by means of a splitting wheel (2) characterized in that the circle, during the splitting operation, is pressed to one side, and that the circle on that side is supported by a supporting wheel(31

2. Device according to claim 1 characterized in that the splitting wheel(2)has an asymmetrical edge(4,5)and that in the fork of the splitting wheel there is disposed a supporting wheel(3)which prevents deflection of the metal circle, ensuring a constant distribution of thickness in the split area.