BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a highly simplified sectional illustration through a device according to the invention, with severed hollow profile arranged therein, and
FIG. 2 shows an illustration similar to that of FIG. 1, but with a hollow profile which is not severed and with a different cutting edge.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a detail of a device 1 for severing a hollow profile 2, shaped according to the internal high pressure forming process, transversely to its longitudinal extent 3. The hollow profile 2 (only partly shown) is produced before the severing by means of an internal high pressure forming process known per se. To this end, a blank (not shown) is inserted into the device 1 and a forming pressure, that is to say an internal high pressure pi, is expediently applied hydraulically to its inner side, the blank expanding in such a way that it comes to bear on its outer side against an inner wall 6, facing the blank, of the device 1. The hollow profile 2 is thus given a wall 12 which is formed in such a way as to be complementary to the inner wall 6 of the device 1.
Both FIG. 1 and FIG. 2 show a longitudinal section through the device 1 according to the invention, only one part above the section plane 14 being shown.
An encircling cutting edge 4 for severing the hollow profile 2 transversely to its longitudinal extent 3 is arranged according to FIG. 1 on an encircling recess 5 which is formed in the inner wall 6 of the device 1. In this case, according to FIG. 1, the encircling recess 5 is of wedge-shaped design in profile, although a geometrically different design, for example a circle-segment-like design, is also conceivable. In general, the recess 5 is configured in such a way that it expands the hollow profile 2 in the region of the encircling recess 5 during the severing. In the process, an encircling funnel-shaped expansion of the hollow profile 2 is produced after its severing by the wedge-shaped recess 5 according to FIG. 1. In the abovementioned embodiment variant with a circle-segment-like recess 5, a bulge-like expansion is therefore to be expected.
According to FIG. 1, the cutting edge 4 is formed at a transition 8 between the inner wall 6 and the recess 5. In this case, according to FIG. 1, the transition 8 is of right-angled and sharp-edged design, a transition 8′ at that end of the wedge-shaped recess 5 which tapers to a point expediently being rounded off, so that the hollow profile 2 can easily come to bear during the expansion or during the severing. However, a sharp-edged transition in the region of the transition 8′ is also conceivable.
The cutting edge 4 required for severing the hollow profile 2 may either be designed as an interchangeable parting blade 9 of the inner wall 6 (cf. also FIG. 2) or as an integral part 10 of the inner wall 6 or may form such an integral part 10 of the inner wall 6. It is conceivable here for the interchangeable cutting edge 4 or the interchangeable parting blade 9 to be releasably fastened to the transition 8 or, according to FIG. 2, for said cutting edge 4 or said parting blade 9 to simply be interchangeably arranged in the recess 5. Alternatively, however, it is also conceivable, in the case of a cutting edge 4 which has become blunt and forms an integral part 10 of the inner wall 6, for part of the device 1 in the region of the cutting edge 4 to be designed to be interchangeable.
The design of the cutting edge 4 both as an interchangeable parting blade 9 and as an integral part 10 offers advantages on the one hand with regard to the simplicity of the exchange of the cutting edge 4 and on the other hand with regard to a reduction in the individual parts required for the device 1.
According to FIG. 1, sealing elements 7 are arranged on both sides and parallel to the cutting edge 4 and are inserted into a receptacle 11 which is incorporated in the inner wall 6. The two receptacles 11 according to FIG. 1 are in this case arranged at a distance from the wedge-shaped recess 5 more or less in the longitudinal direction 3. The sealing elements 7 which are inserted into the receptacles 11 project in this case at least slightly beyond the inner wall 6, so that a sealed-off connection is obtained when the wall 12 of the hollow profile 2 comes to bear against the sealing elements 7. The higher the internal pressure pi, the greater the contact pressure of the wall 12 against the sealing elements 7 and thus the greater the sealing effect itself.
In contrast to FIG. 1, only one receptacle 11, here a rectangular receptacle 11, is provided in FIG. 2, the two sealing elements 7 being inserted into said receptacle 11 directly adjacent to the cutting edge 4 or the parting blade 9. Both the sealing elements 7 in FIG. 1 and the sealing elements 7 in FIG. 2 may be formed from plastic, in particular an elastomer. As a result, they can be produced cost-effectively and simply and can be individually adapted with regard to their specific properties, such as thermal stability and/or compressive strength for example, to the requirements for the device 1 or the parting operation. In addition, such plastic seals can be easily fitted and removed and have an extremely long life due to the current choice of materials.
According to FIG. 2, the sealing elements 7 conceal the cutting edge 4 and do not release the latter until after certain deformation, i.e. until after a certain internal high pressure pi. From this internal high pressure pi, for example the calibrating pressure, the wall 12 of the hollow profile 2 comes into contact with the cutting edge 4 or the parting blade 9, as a result of which the parting operation is initiated. In contrast to FIG. 1, two expanded parting sections (not designated in any more detail) of the hollow profile 2 are produced in the device 1 according to FIG. 2 when the hollow profile 2 is severed.
In addition, in the embodiment variant according to FIG. 2, it is conceivable for the cutting edge 4 or the parting blade 9 to either be arranged in the recess 5 in a pressure-stable manner or else be additionally pressed against the hollow profile 12 by means of a counterpressure.
In both embodiment variants, the device 1 can be dimensioned in such a way that the hollow profile 2 is severed at a calibrating pressure at which the operation for forming the hollow profile 2 has essentially been completed or at which the wall 12 bears against the inner wall 6 in such a way as to follow the shape.
It is generally the case that both the embodiment variant in FIG. 1 and the embodiment variant in FIG. 2, with regard to their geometrical configurations, for example the geometrical configuration of the recess 5 or of the recess 11 or an arrangement angle (not designated in any more detail) of the cutting edge 4 relative to the hollow profile 2, merely represent one embodiment variant and do not in the least claim completeness, so that other favorable geometrical arrangements and embodiment variants are also included.
In summary, the essential features of the solution according to the invention can be characterized as follows:
In a device 1 for severing a hollow profile 2, shaped according to the internal high pressure forming process, transversely to its longitudinal extent 3, the invention makes provision for sealing elements 7 to be provided on an inner wall 6 of the device 1, these sealing elements 7 being arranged on both sides of an encircling cutting edge 4. The cutting edge 4 is in this case arranged in or at an encircling recess 5 and, for example, is of wedge-shaped design in profile.
The invention therefore simplifies the construction of the device, enables the hollow profile to be severed jointly with or separately from the forming process, produces no material scrap and is also suitable for cutting off dome caps and for end trimming.
Patent Application
20080022833
