EP0266545B1 - Method and device for marking rotationally-symmetric moulded articles - Google Patents

Abstract

The method and device are used for marking rotationally symmetric moulded articles, in particular sleeves (18) of hose fittings of hose lines (14), by means of a radial press. The latter has several radially movable, driven pressing jaws (6) arranged around the axis (S-S) of symmetry of the press and moulded article. Arranged in at least one press jaw (6) is a recess (19), in which an arrangement of rows of plate-shaped embossing dies (20) is accommodated, the embossing sides of which lie in the working surface (7). It is thus possible to produce the marking during the pressing operation of the moulded articles in a single operation and by means of one and the same device. The degree of radial deformation is preferably selected to be so high that the material of the moulded articles flows in the axial direction over at least some of the embossing dies (20). <IMAGE>

Description

The invention relates to a method for identifying rotationally symmetrical pressed parts, in particular sleeves of hose fittings, by means of at least one row arrangement of individually exchangeable stamping dies running in the direction of the axis of symmetry.

According to the DIN standard 20066, labeling is required for fully assembled hose lines. Hose lines are understood to be a unit consisting of an elastic hose and two fittings mounted at the ends. The label should contain the following information: manufacturer's label, year and month, maximum permissible dynamic operating pressure. Ultimately, the marking is part of the safety regulations. It is important that the date indicates the manufacture of the hose line, i.e. the union of hose and fittings, and not the date of manufacture of the individual parts.

A hose bursting at a pressure of 1000 bar, for example, poses a considerable danger to people who are nearby. From the burst hose escaping hydraulic oil poses an enormous environmental hazard: the oil must be removed by chemical means; Any contaminated soil must be removed by dredging. This can involve significant amounts of hydraulic fluid. For example, some construction machines contain quantities of oil of up to 500 liters to operate their numerous hydraulic drives. At least part of this oil is under the action of pressure accumulators, so that a not inconsiderable part of this oil can escape to the environment in the event of a leak. The quality requirements for hose assemblies are therefore considerable, and in the event of damage, the required labeling serves not least to hold the manufacturer responsible if necessary, so that the labeling requirement is a very effective means of guaranteeing the choice of materials and the quality of workmanship.

It is known to provide hoses with the required marking at regular intervals, which of course only says something about the properties of the hose and its manufacturer. In addition, there is a risk that such a marking will gradually be rubbed off when the hose is subjected to high mechanical stress.

It is also known to provide the outer sleeves of hose fittings with embossed markings. For manufacturing reasons, the marking is applied to large numbers of sleeves before they are gradually fed to their end use. So there can be a considerable amount of time between the date of labeling and the processing date. The labeling of small quantities just taken from the warehouse would be complex and is therefore not carried out in practice. In addition, readability becomes one before pressing the sleeve generated marking affected by the pressing process.

Regarding the term "hose fittings", reference is made to the following: a hose fitting generally contains a tubular part with connecting elements for connecting the finished hose line to a pressure source and / or a consumer, and with a profiled end which is inserted into the hose end. On this hose end, the elastomer surface layer of which was previously removed, there is a sleeve which is pressed under high pressure onto the hose end and onto the profiled end of the tubular part located therein, as a result of which the hose is reliably pressed in. Various radial presses are commercially available for such a process. Such a press is described by way of example in DE-PS 28 44 475.

It is also already known to mark the thick-walled sleeves for hose fittings on the entire circumference by means of a roll embossing machine before they are plugged onto the hose end and pressed with it. This marking is distributed radially around the circumference of a sleeve and is inevitably interrupted or damaged by the press jaw impressions (“press pattern”) and thereby difficult to decipher, if not rendered illegible. Apart from the fact that in this case too there is no compulsory temporal assignment between the marking and pressing process, such a method requires the presence of a complex embossing device and an additional operation. As a result, an embossing device must also be provided at each location of use for a radial press for the production of hose lines. In principle, it is also designed as a press.

The invention is therefore based on the object of specifying a method of the type described in the introduction, in which an additional method step and a special embossing device can be dispensed with and in which there is also a fixed time allocation between the manufacture of the hose line and its identification.

The object is achieved in the method described at the outset according to the invention in that the marking is produced during the pressing process of the pressed parts by a radial press with a plurality of pressing jaws which are arranged to be radially movable around the axis of symmetry and at least one of which has a pressing jaw in its working surface the row arrangement of the individually exchangeable embossing dies is provided.

When using the method according to the invention, the prescribed marking is thus generated by a single, already indispensable process step, namely by pressing the sleeve on. This does not require a special operation or a special stamping device with its own drive. In addition, there is a fixed time allocation between the manufacture of the hose line and its identification, so that the date of the embossing tamper-proof indicates the date of manufacture of the complete hose line.

Since such a hose line usually has two ends which are provided with corresponding hose fittings, the method according to the invention also gives the possibility of providing both ends of the hose line, ie both sleeves, with the required identification. This has the additional advantage that if the hose line is completely severed in the area of the hose, each of the two ends can provide information about the manufacturer and the characteristic data of the hose. The labeling is also towards everyone Wear and tear that occurs in practice is safely protected and accompanies the hose line throughout its life like a birth certificate. Storage of large quantities of pre-stamped sleeves is completely unnecessary.

The possibility of simultaneously producing the pressing and embossing process was surprisingly found: due to the radial compression of the sleeve against the considerable resistance of the hose, which is usually provided with a metal insert, and the tubular part located in the hose, the sleeve is inevitably axially elongated by about 2 -4%. This elongation is based on a fictitious press center that is approximately in the middle of the sleeve length. The material must necessarily flow over the profiled embossing surface of the embossing stamp, so that these are exposed to considerable axial forces. It has surprisingly been found, however, that suitable embossing or embedding of the embossing dies can ensure that the embossing dies can absorb such transverse forces.

It is even particularly advantageous if the radial degree of deformation of the pressed parts is chosen so high that its material flows in the axial direction over at least part of the stamping dies. The image of the dies is surprisingly clear and unambiguous at the ends of the row arrangement of the dies; on the other hand, however, it also shows that the embossing was produced when the sleeve was pressed, so that the knowledgeable observer can recognize the temporal correspondence of presses and embossing.

The invention also relates to a radial press for carrying out the method according to the invention. A radial press with several around the axis of symmetry of the press and the press part arranged radially movable and driven by drive means pressing jaws with work surfaces is known for example from DE-PS 28 44 475, but without any possibility of identifying the pressed parts.

To achieve essentially the same object, such a radial press is characterized according to the invention in that a recess is arranged in at least one press jaw, which opens into the work surface, in that a row arrangement of plate-shaped stamping dies (`` stamping types '') is arranged in the recess, the stamping side of which in lies essentially in the working surface of the press jaw, the row arrangement running in the direction of the axis of symmetry, and in that the recess at the ends of the row arrangement is provided with flat and mutually parallel support surfaces for the support of the end stamps.

What is particularly important here is the last partial feature, which enables the surface of the embossing dies to be supported at the ends of the recess. The recess is preferably cuboid, the longest axis of the cuboid extending essentially parallel to the axis of symmetry of the press and the pressed part. As a result, the ends of the recess lie opposite one another in the axial direction, the support surfaces lying essentially in radial planes. Attempts to brace the dies against one another with a pressure screw, as in the case of a pure stamping press, have in any case not been successful: the stamps adjacent to the pressure screw break during the pressing process.

The embossing dies themselves have the shape of small cuboids, the largest, plane-parallel boundary surfaces of which directly abut one another in the row arrangement, as is known from so-called end scales. By the invention Storage of such a row arrangement between flat support surfaces precludes any risk of breakage of individual dies.

It is particularly advantageous if the recess contains at one end a wedge-shaped pressure body, which on one side has a support surface for the abutting die and on its opposite side has a first inclined plane, which on a complementary second inclined plane in the press jaw is displaceable, such that the row arrangement of the dies can optionally be placed under pressure and relaxed by relocating the pressure body.

Such a wedge-shaped pressure body enables the large-area transmission of the forces exerted by the axial elongation of the pressed part on the stamping dies.

Further advantageous embodiments of the subject matter of the invention emerge from the remaining subclaims; their advantages are explained in more detail in the detailed description.

An example of a conventional radial press and its modification according to the invention are explained in more detail below with reference to FIGS. 1-5.

Fig. 1

einen Radialschnitt durch eine Radialpresse herkömmlicher Bauart,

Fig. 2

einen Axialschnitt durch eine Preßbacke mit erfindungsgemäß eingesetzten Prägestempeln,

Fig. 3

eine Draufsicht auf die Preßbacke gemäß Fig. 2 in Richtung des Pfeils III in Fig. 2,

Fig. 4

einen Radialschnitt durch die Preßbacke gemäß Fig.2 entlang der Linie IV-IV und

Fig. 5

eine Draufsicht auf die Hülse einer Schlaucharmatur mit einem Preßmuster und einer Kennzeichnung mittels der Preßbacken nach den Figuren 1 - 4.

Show it :

Fig. 1

a radial section through a radial press of conventional design,

Fig. 2

an axial section through a press jaw with embossing dies used according to the invention,

Fig. 3

2 in the direction of arrow III in FIG. 2,

Fig. 4

a radial section through the press jaw according to Figure 2 along the line IV-IV and

Fig. 5

a plan view of the sleeve of a hose fitting with a press pattern and a marking by means of the press jaws according to Figures 1-4.

In Fig.1 the essential parts of a radial press 1 are shown, which includes a rear flange plate 2 with a pressure ring 3, which is designed as a hollow piston and is surrounded by a cylinder 4 with a cylinder jacket 5, one between itself and the pressure ring 3 here includes invisible annular cylinder space. When the cylinder chamber is pressurized, the pressure ring 3 and cylinder 4 perform a relative telescopic movement to one another, which leads to a radial displacement of press jaws 6, which consist of a press jaw base body 6a and a (exchangeable) press jaw attachment 6b. The pressing jaws 6 are explained below as a unit, the nature of the pressing jaw attachments 6b naturally being decisive for the pressing and embossing process. The press jaws are equipped with work surfaces 7, which give the pressed part its final shape.

To bring about a radial movement of the pressing jaws 6, the pressure ring is provided on its inside with a conical control surface 8, on which the pressing jaws 6 are supported with their conical outer sides. In the axial direction towards the viewer, the pressing jaws 6 are supported on an abutment, not shown here, on which So-called sliding blocks 9 are attached, which are used for exact radial guidance of the pressing jaws 6. Flange plate 2 and the not shown, also plate-shaped and congruent abutment are guided relative to each other by guide pins 10 and pressed apart by compression springs 11 when the hydraulic drive is relieved. The outward movement of the pressing jaws 6 into the position shown in the lower part of FIG. 1 is brought about by tangential return springs 12, with spaces 13 being established between the individual pressing jaws. As soon as pressure medium is applied to the cylinder 4, the control surface 8 pushes the pressing jaws 6 radially inwards until the working surfaces 7 form a practically closed circle, as is shown in the upper half of FIG. 1. The spaces 13 are pushed together to a minimal gap.

2 now shows the details of a press jaw 6 according to the invention (more precisely, it is the exchangeable press jaw attachment, which is, however, insignificant for the description of the invention). The press jaw 6 abuts with its working surface 7 at the end of a hose line 14 shown in dash-dot lines, of which a section of the hose 15, the tubular part 16 are shown with a connecting element 17. The tubular part 16 extends into the interior of the hose 15; in the area of the overlap is the sleeve 18, the pressing and labeling of which is at issue here. The remaining press jaws have been omitted for the sake of simplicity.

As can be seen with the addition of FIGS. 3 and 4, a recess 19 is arranged in the press jaw 6, which, with the exception of its right-hand end, is cuboid and opens into the work surface 7. In the work area lies, more precisely, one of the narrow long sides of the cuboid cavity. A row arrangement of platelet-shaped embossing dies 20 is accommodated in the recess 19, the embossing sides of which are provided with so-called "letters" (mirror image in FIG. 3). The embossing sides 21 are essentially in the working surface 7 of the press jaw. The "letters" are raised characters or numerals, as is known from embossing stamps, how they are used, for example, as "stroke numbers" and as they have previously been used in so-called embossing machines. The dies usually consist of a wear-resistant and very hard manganese-vanadium steel (e.g. 90MnV8). The required protrusion of the embossing letters or embossing numbers on the work surface 7 can be determined by simple tests. In order to be able to vary this dimension slightly, there is an exchangeable cuboid pressure plate 22 made of hardened steel in the recess 19. By using printing plates of different thicknesses, the required adjustment of the dimension mentioned can be carried out.

The row arrangement of the dies 20 runs in the direction of the axis of symmetry S-S (FIG. 2), the course not having to be exactly parallel to the axis of symmetry S-S, but preferably being parallel.

The recess 19 is provided at the ends of the row arrangement with flat and mutually parallel support surfaces 23 (left) and 24 (right) for the support of the end dies 20a and 20b.

As can be seen in particular from FIG. 2, the recess 19 contains at its one (right) end a wedge-shaped pressure body 25, which has the one support surface on one side 24 for the abutting embossing die 20b and on its opposite side has a first inclined plane 26 which can be displaced on a complementary, second inclined plane 27 in the pressing jaw 6, in such a way that the row arrangement of the embossing dies 20 is caused by displacement of the pressure body 25 is optionally pressurizable and can be relaxed. As can be seen from FIGS. 2 and 3, the end face of the pressure body 25, which is particularly visible in FIG. 3, is set back from the work surface 7, so that the pressure body 25 is not acted upon by surface forces of the sleeve 18, which loosens the dies Would have consequence.

From Fig. 2 it also follows that the pressure body 25 is mounted displaceably in the radial direction to the axis of symmetry S-S. From Fig. 2 it also appears that the pressure body 25 is associated with a clamping screw 27 mounted in the press jaw 6, through which the desired clamping effect can be brought about. In the case shown, the clamping screw 27 is a pressure screw. But it is also conceivable to reverse the pressure body 25 and the angular position of the inclined planes 26 and 27 so that the pressure body can be pressed against the die 20 by using a tension screw instead of the clamping screw 27. In this case, however, a pressure exerted on the end face (e.g. also due to metal abrasion) would increase the clamping forces, so that it would be more difficult to release the lock.

As can further be seen from FIG. 2, the recess 19 in the press jaw 6 has a base 28 which serves to (indirectly) support the dies 20. The interchangeable pressure plate 22 is located between the dies 20 and the base 28. Around the dies 20 for the purpose of exchange and / or regrouping to be easier to remove, a pressure screw 29 is arranged in the bottom 28 in the center under the pressure plate 22, through which the pressure plate 22 can be raised so far relative to the bottom 28 when the press jaw 6 is removed that the dies 20 can be comfortably gripped by hand.

In FIG. 4, the dash-dotted rays symbolize the center lines and directions of movement of the individual press jaws 6. The press jaw 6, drawn in full lines, contains the row arrangement of stamping dies 20. It is readily possible to provide further press jaws with corresponding recesses and stamping dies, for which purpose preferably the opposite one Press jaw is used. It is in particular possible to subsequently replace press jaws or press jaw attachments, even in existing machines, by press jaws or press jaw attachments which are provided with the row arrangement of press punches according to the invention. In this way it is easily possible to convert an existing press without an embossing device into a press with an embossing device.

In Fig.5 the already pressed and provided with a marking 30 sleeve 18ʹ is shown, on which the information according to the DIN standard 20066 is included. The line pattern on the sleeve 18ʹ indicates that a so-called "press pattern" is formed on the surface of the sleeve, the individual surfaces 18a of which represent the impression of the working surfaces 7. Between these surfaces are line-shaped areas 18b that have not been touched by the work surfaces 7. The entire surface of the sleeve 18ʹ can, however, be described as essentially cylindrical. If the marking 30 is arranged slightly recessed in the surface, it is also very largely protected against mechanical damage.

Claims (8)

1. Method for marking rotationally symmetrical pressed parts, in particular of sleeves of pipe assemblies, by means of at least one series arrangement of individually exchangeable stamp dies extending in the direction of the axis of symmetry, characterised in that one produces the marking during the pressing process of the pressed parts by a radial press with several press jaws, which are arranged to move radially about the axis of symmetry and whereof at least one press jaw is provided in its working surface with the series arrangement of individually exchangeable stamp dies.
2. Method according to Claim 1, characterised in that the degree of radial deformation of the pressed parts is chosen to be so high that the material thereof flows in the axial direction over at least part of the stamp dies.
3. Radial press for carrying out the method according to Claim 1, with several press jaws with working surfaces, able to move radially and arranged around the axis of symmetry of the press and pressed part and able to be driven by drive means, characterised in that located in at least one press jaw (6) is a recess (19), which opens into the working surface (7), that located in the recess is a series arrangement of plate-shaped stamp dies (20), whereof the stamp sides (21) lie substantially in the working surface of the press jaw, the series arrangement extending in the direction of the axis of symmetry (S-S) and that at the ends of the series arrangement, the recess (19) is provided with flat support surfaces (23, 24), which are parallel to each other, for supporting the terminal stamp dies (20a, 20b).
4. Radial press according to Claim 3, characterised in that at one end the recess (19) contains a wedge-shaped pressing member (25), which on its one side comprises a support surface (24) for the adjoining stamp die (20b) and at its opposite side comprises a first inclined plane (26), which is able to slide on a complementary, second inclined plane (27) in the press jaw (6) so that by shifting the pressing member (25), the series arrangement of the stamp dies (20) can be optionally placed under pressure and relieved of pressure.
5. Radial press according to Claim 4, characterised in that the pressing member (25) for tensioning and releasing the stamp dies (20) is mounted to slide in the radial direction with respect to the axis of symmetry.
6. Radial press according to Claim 4, characterised in that associated with the pressing member (25) is a tightening screw (27) mounted in the press jaw (6).
7. Radial press according to Claim 3, characterised in that the recess (19) in the press jaw (6) comprises a base (28) for supporting the stamp dies (20) and that located between the stamp dies (20) and the base (28) is an exchangeable pressure plate (22).
8. Radial press according to Claim 7, characterised in that located in the base (28) of the press jaw (6), centrally below the pressure plate (22) is a pressing screw (29).

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