Pipe joints or couplings – Nonmetal to metal – Internal member
Reexamination Certificate
1999-03-26
2001-10-02
Nicholson, Eric K. (Department: 3627)
Pipe joints or couplings
Nonmetal to metal
Internal member
C285S259000, C029S890144
Reexamination Certificate
active
06296283
ABSTRACT:
The invention relates to a hose connection with a hose mount in the form of a sleeve for accommodating a spout and a hose end, to which the sleeve is squeezed.
Hose mounts of this nature are used to releasably screw hoses, for example hydraulic hoses, to connections on machines. This is carried out with the aid of a hose connection having a spout which engages in the hose, for example a high-pressure hose, and is provided with external grooves or ribs and a stop bead, and a screw thread which is arranged on the other end and has a separate union nut for screwing it to a mating connection, for example a pipe end. In view of the pressures in the hose, which are sometimes high to very high, it is necessary to provide a permanent connection, which is suitable for the pressure used, between the mount or sleeve, the hose end and the spout.
Therefore, conventional hose mounts have internal ribs which are approximately triangular in cross section, run transversely with respect to the longitudinal axis of the hose mount, penetrate more or less deeply into the flexible hose material when the parts are pinched together, and anchor the mount in this material.
The internal ribs make conventional hose mounts expensive, because the sleeves are usually produced from solid material by chip-forming machining. To do this, a round bar is firstly cut to length and is then bored. Then, using a special tool, the internal ribs are machined out of the remaining tubular solid material.
This process is extremely time- and material-consuming, since the material of the finished mount constitutes only approximately 25 to 30% of the original volume of the bar section which was cut to length. Consequently, approximately 70 to 75% of the original volume is lost in the form of chips. Furthermore, only steels which are readily machinable and consequently have higher lead, sulphur and/or selenium contents are suitable as materials for the hose mount. However, depending on the particular application, it would be desirable to have a freer choice of materials. In addition, the introduction of heat when soldering or welding may lead to microstructural changes which reduce the strength of the material.
Although the loss of material when pipes are used to produce hose connections by means of chip-forming internal machining is considerably lower, the advantage in terms of costs is not significant, since the pipes must have a comparatively great wall thickness and generally represent considerably more expensive starting materials than round bars of the same diameter. Correspondingly thick-walled pipes are required in order to be able to form the internal ribs out of the pipe wall by machining.
The invention is based on the problem of providing a hose connection with a hose mount which can be produced in a short time and with little or no loss of material.
This problem is solved by a hose connection with a hose mount made from a sleeve which comprises, for example, cold-rolled deep-drawing sheet or strip metal and has cold-formed projections which face inwards, for example in the form of internal ribs, protuberances and points which run all the way around.
A hose mount of this nature can be produced from suitably dimensioned rectangular sheet-metal blanks using cold-rolled strip, the width of which corresponds to the length of one edge of the blank. By simply cutting the strip with the aid of a shear, the blanks can easily be produced with two edges of any desired length; they are then provided with the projections on one side with the aid of a cold-working tool. This may, for example, be carried out with the aid of a roller which is provided with ribs and which presses internal ribs out of the sheet-metal blank. This results in a blank which is provided with grooves on one side and with ribs on the other side. Instead of the ribs, or even in addition to the ribs, the blank may—using a type of spiked roller—be provided with indents and on the other side with points by cold-forming.
The cold-formed blank is then bent into a cylinder. The abutting edges are then permanently joined together by welding or soldering. Before being bent into a cylinder, however, the blank may also be bent off on one side in the direction running transversely to the sleeve axis, in order to produce a sleeve which on one side is reduced to a smaller opening.
In order to improve the service life and the dimensional stability of the sleeve when soldering or welding, the abutting edges may also be in meandering form. Such a profile of the abutting edges is produced if, in the region of an abutting edge, the blank, by stamping, is provided with tongues and the opposite side of the blank is provided with complementary, approximately &OHgr;-shaped recesses. The two mutually opposite edges do not have to have identical contours or be congruent, since the strength of the initially form-fitting connection produced when bending into a cylinder is increased, at the abutment area, if the edges of the blank which come into contact with one another undergo cold deformation or even cold welding at this location.
When producing the sleeve, a blank which is bent off on one side can be deformed in such a way that the sleeve acquires a collar which projects inwards. In this case, the considerably smaller free cross section of the collar results in a considerable deformation of material, with a correspondingly high level of work hardening. However, this can be largely avoided if the edge of the blank formed during the bending-off operation is firstly provided, by stamping, with, for example, wedge-shaped incisions, the mutually opposite edges of which come to bear against one another when the collar is being cold-formed.
The hose mount according to the invention is suitable in particular for hose connections as described in the documents of German patent application 196 18 819.9. The content of these application documents is therefore to be regarded as a constituent part of the present invention.
These hose connections comprise a pipe piece which on one side is formed as a standard spout, but on the screw-thread side merges, via an outer corrugation, into an outer bead. Both features can readily be produced by simple cold-forming, essentially by widening and, for example, axial compression in the form of inwards folding.
Since the bead—in contrast to a conventional groove for an O-ring—does not have to be machined or rolled in using a hard-metal tool, but rather is produced by compression or depression in the course of inwards folding, an advantageous bead cross section is produced without a high level of outlay.
The bead is preferably situated at the foot of a funnel-shaped widened section which forms the transition to the cross section of the mating connection or pipe end.
In this case, the hose connection may, on the screw-thread side, be approximately in the form of two cones which are connected to one another via a constriction. The bead then runs in the area of the constriction and advantageously has a triangular cross section which, when screwed to the mating connection, is filled to a greater or lesser extent by the sealing ring, which is then considerably deformed.
A hose mount which is provided with points provides a particularly secure connection, since the points penetrate into the diamond-shaped meshes of the hose fabric. The tear resistance is particularly high if this is a wire fabric or wire mesh.
In order to avoid a funnel-shaped widening of the sleeve when forming the internal collar, an annular disc may be arranged in the area of the bending edge, around which disc the bent-off strip of the metal sheet is laid when producing the internal collar.
The interior of the hose mount may also be provided with one or more stops for the hose end, in order to hold the hose end at a certain distance from the internal collar. When pinching together the hose and the nipple, on the one hand, and the sleeve, on the other hand, this distance allows axial expansion into the free space between the stops and the internal collar.
Since the hose mount according to the
Dipl.-lng. K. Dietzel GmbH
Merchant & Gould P.C.
Nicholson Eric K.
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