WO1983002737A1

WO1983002737A1 - Apparatus for pressing tubular parts

Info

Publication number: WO1983002737A1
Application number: PCT/EP1983/000024
Authority: WO
Inventors: Karl Sauder
Original assignee: Karl Sauder
Priority date: 1982-02-04
Filing date: 1983-02-01
Publication date: 1983-08-18
Also published as: ATE19967T1; HUT36734A; EP0100334B1; DK455983A; AU1158683A; ZA83745B; IT1167313B; EP0100334A1; DK455983D0; AT376589B; ES8402409A1; FI833575A0; NO833584L; ES519509A0; NO154185B; US4696085A; NO154185C; IT8367114A0; NZ203168A; BR8305746A

Abstract

Apparatus for pressing tubular parts, particularly for pressing or clamping pipe adaptors against rigid or flexible pipes and sleeves. There is provided a plurality of clamping jaws (2), which are spring actuated, radially displaceable and connected to an annular piston (15). The piston (15) is hydraulically displaced towards the clamping jaws (2) and returns to its rest position. The surface (25) of the piston which effects the return of the piston (15) represents only a fraction of the surface of the piston (18) which provides for the forward stroke of the piston (15). The end of the piston (15) adjacent to the clamping jaws (2) meshes in an annular hydraulic cylinder (17), the whole of the cross-section of the piston (15), larger at that one end, forming the surface (18) of the piston which provides for it forward stroke.

Description

DEVICE FOR COMPRESSING TUBULAR PARTS

The invention relates to a device for pressing tubular parts, in particular for pressing or pressing pipe connectors onto pipes, sleeves or hoses, consisting of a plurality of spring-loaded clamping jaws which are adjustable in the radial direction and a piston which is annular in cross-section and which acts on the clamping jaws. the inside of the end region facing the clamping jaws is expanded conically, the clamping jaws with their radially outer boundary surfaces bearing on the conical extension with a corresponding angle of inclination, and the piston being hydraulically displaceable in its rest position in the direction of the clamping jaws.

Some embodiments of such devices are already known. In particular, such a device is used to press pipe fittings onto the ends of hydraulic hoses. Such pipe connectors usually consist of two coaxial tubular sections which are connected at one end to each other and the pipe connecting parts, e.g. Thread sections, wear. An annular gap remains between the two tubular parts, the end of a hose being inserted into this gap. These attached pipe connectors are then inserted between the jaws of the device and pressed radially, so that the end of the hose used is firmly clamped between the two tubular sections.

In such a known device, a plurality of clamping jaws are arranged around an axis and located within a press-on element which has a conically tapering inner surface. A cylindrical hydraulic piston is provided here in order to press the pressing element against the To move the jaws, whereby the jaws are moved against each other in the radial direction by this displacement and the conical surfaces abutting each other. The hose connection inserted between the clamping jaws is thereby pressed. There are also measuring devices which indicate whether the desired final outside diameter has been reached. For this purpose, the operator must observe the grinder in order to stop the operation of the device at this point. In such a device, relatively large hydraulic cylinders must be used to achieve the necessary contact pressure. If only a low operating pressure is available, there are still far more serious design problems since the device then becomes too bulky.

Attempts have also already been made to provide a large-area piston which is aligned axially with respect to the jaw axis. In such an embodiment, however, the device is only accessible from one side, so that only tailpipe connectors can be impaled. A socket connection of a hose line, for example, cannot be carried out with such an arrangement. In addition, a plurality of spring-loaded spindles are required in this arrangement in order to retract the actuating element for the clamping jaws again into the rest position. This in turn requires an elaborate and playful construction. If these spindles with the springs are not arranged, there is only the possibility of resetting them through the dead weight of the actuating member and the spring-loaded clamping jaws. The working speed is significantly reduced and there are also disruptions in the workflow. In another known device, in which the clamping jaws are actuated by the direct radial action of a pressure medium, difficulties arise because no one can reach the necessary contact pressure. For this purpose, a pressure would have to be built up by the pressure medium, which would only be manageable with an oversized design of the device.

In another known device, a piston is displaceably mounted in a cylindrical housing with a stop collar, which is also provided with a stop collar, which is directed outwards. A cylinder space is created between the outer surface of the piston, the inner surface of the cylinder and the two mutually facing boundary surfaces of the stop collars, which can be acted upon hydraulically. Even with such an arrangement there are space problems and thus correspondingly large designs, since practically the actual piston-cylinder unit must be carried out laterally outside of the actuating part designed as a piston for the clamping jaws. In addition, in such a known embodiment it is to be regarded as disadvantageous that a large number of springs must be provided in order to return the actuating element, that is to say the piston, to its rest position after pressing. On the one hand, this means a corresponding expenditure of material and space, so that the construction becomes complex, and on the other hand, this additional spring force must always be overcome when pressing.

Furthermore, a pressing device is known, which is actuated by a double-acting piston. The pressing device is thus moved both forward and backward by hydraulic force. In this case, an inner and an outer cylindrical element are provided, two annular chambers being formed between these two elements. be formed. The inner element acts as a hydraulic cylinder and the outer element as a hydraulic piston. In order to be able to build up sufficient pressure for the pressing, a correspondingly large piston area is required. A correspondingly large, inwardly projecting collar must be provided to achieve the necessary piston area. However, since this piston must also form a cylinder wall, a large dimension is necessary, at least in the transition area between this outer wall and the inwardly projecting collar. In addition, a relatively thick design is required for the cylinder, since the projecting collar has to absorb the enormous forces. There is no possibility of reaching a support from an opposite wall, since this collar is freely cantilevered.

The object of the invention is therefore to create a device of the type described at the outset which enables a simple construction which is small in terms of space.

This is achieved according to the invention in that the effective piston area for the return of the double-acting piston is only a fraction of the piston area for the advance of the same, that the end of the piston facing away from the clamping jaws engages in an annular hydraulic cylinder and that the effective piston area for the advance of the piston is formed at the free end thereof facing away from the clamping jaws and runs parallel to the bottom of the annular cylinder, the piston having the largest cross-sectional area at its end forming the effective piston surface for the feed.

In this respect, according to the present invention Significant advantage achieved when the effective piston area for the hydraulic return of the piston is only a fraction of the piston area for the same feed. This provides a vote on the forces required, since a much larger piston area must be available during the pressing process than when returning the piston to the rest position.

Only through the possibility that the piston is guided in an annular hydraulic cylinder and the effective piston surface for the advancement of the piston at the free end facing away from the clamping jaws is it possible to achieve substantial improvements in terms of design. The bottom of the cylinder is thus practically carried by two sleeves, that is, by the ring-shaped cylinder limitation, whereby it is possible to dimension both the inner and the outer ring of the cylinder much smaller. In the case of the piston cross section, this has a particularly favorable effect, since here practically the entire cross section of the annular piston can be used for the application of the force, which can only be achieved if this effective piston surface is formed by the end of the piston. Since only a very small piston area is required for the return of the piston, a corresponding offset of the piston in the corresponding area hardly means a cross-sectional weakening, so that the forces can be fully transmitted in the axial direction by the piston without there being any danger of shearing off or could result in bending of protruding parts.

In addition, an important advantage of such an arrangement is that all the guide surfaces between the piston and the cylinder are covered towards the outside, so that they are not accessible for mechanical damage. Further features according to the invention and special advantages are explained in more detail in the following description with reference to the drawings. 1 shows a device according to the invention in an oblique view; 2 shows a section through the device for pressing; Fig. 3 shows schematically an adjustable device for switching a hydraulic valve when a certain compression diameter is reached.

The device shown in Fig. 1 consists essentially of a Zylinderkδrper 1, in which the jaws 2 and the actuators for the same are housed, as well as a housing 3 supporting this cylinder body 1 In the housing, a hydraulic valve is housed, via which the supply of the pressure medium the actuator can be regulated. The necessary pressure can be achieved via a hand pump 4 or corresponding external connections. Furthermore, an adjusting device 5 with an adjusting button 6 and a scale is provided. With this device, as will be explained in detail, the desired final diameter of the to be pressed

Part can be set. An actuating handle 7 is also provided, by means of which the hydraulic valve can be switched over. As can already be seen from this Fig. 1, the device according to the invention can be manufactured in a very small but compact design, so that such a device for both stationary use and for individual use in any operation, at any location and at any point suitable is. Instead of a third-party connection and in addition to a hand pump, an electrically operated pump can also be accommodated in the housing 3 in order to build up the necessary pressure.

The construction of the device according to the invention can essentially be seen in the longitudinal section through the device according to FIG. 2. There are several approximations Sector-like adjoining jaws 2 are provided, various inserts being able to be attached to the inner boundaries of these jaws, depending on the desired end diameter range. These jaws 2 are adjustable in the radial direction and spring-loaded against each other, with springs 8 being inserted into corresponding bores 9 between two jaws. At their outer boundaries, the clamping jaws are designed with conical lateral surfaces 10 and 11 falling off towards the two ends. The conical surface 11 is supported on a conical extension 12 of a cone ring 14 and the conical surface 10 on a conical extension 13 of the piston 15. The piston 15 acts as an actuator for the jaws 2, so that when the piston 15 is moved in the direction of arrow 16 Clamping jaws 2 are pushed against each other in the radial direction and are also slightly moved in the axial direction, since they perform a uniform relative movement both to the piston 15 and to the cone ring 14.

The piston 15 is annular and used in the embodiment shown in an annular hydraulic cylinder. The effective piston surface 18 for the advance of the piston 15 is formed on the free end of the piston 15 facing away from the clamping jaws 2 and runs parallel to the bottom 19 of the annular hydraulic cylinder 17. The entire cross-sectional area of the piston 15 can thereby be utilized without additional stop bars or a corresponding large stop collar should be provided to form a piston surface. The effective piston surface 18 is therefore attached to the area of the largest cross-sectional area of the piston 15, so that the structural dimensions of the piston 15 can also be kept very small.

The ring-shaped hydraulic cylinder 17 can also if it's very easy to set up. This is formed by an outer cylinder sleeve 20 and a coaxially inserted pipe section, the cylinder base 19 connecting in one piece to the pipe section 21 used. This enables very simple production with turned parts.

At its end facing the piston surface 18, the piston has a circumferential collar 22 with an outer diameter that is larger than the remaining area of the piston 15. The outer boundary 23 of the hydraulic cylinder 17 is designed at least over the displacement area of the collar 22 with an enlarged inside diameter corresponding to the outside diameter of the collar 22. This creates an annular cylinder space which is enclosed on the one hand by the inner boundary 23 of the outer cylinder sleeve 20 and on the other hand the piston outer surface 24.

The boundary of the collar 22 facing away from the piston surface 18 forms a piston surface 25 which is only a fraction of the piston surface 18. With this very simple measure according to the invention, not only can hydraulic compression take place, but also hydraulic return of the piston 15 to its rest position.

It is also possible to provide an inwardly projecting collar 27 in the area of the inner boundary 26 of the piston 15 in order to achieve a relatively short guide surface for the piston 15 within the hydraulic cylinder 17. Sealing rings 28 or other sealing elements are used in the area of these collars 22 and 27. Another sealing ring 29 is provided at the transition area between the inner boundary 23 with a larger diameter and the inner boundary 30 with a smaller diameter. This sealing ring 29 effects a seal when the piston 15 is returned to the rest position. The cylinder space 31 thus formed does not weaken the cylinder sleeve 20 or the piston 15, this cylinder space 31 is sufficient but fully out to allow proper return of the piston 15.

On the outer edge of the bottom 19 of the hydraulic cylinder 17 and optionally also on the outer edge of the piston surface 18 groove-like depressions or bevels are provided, which together form a circumferential annular channel when the piston 15 is at rest. The supply line 34 for the pressure medium opens into this annular channel, so that even if the piston surface 18 lies directly on the base 19, the pressure medium can penetrate and cause the movement of the piston 15 in the direction of arrow 16.

The supply line 35 for the pressure medium for resetting the piston 15 opens near the cylinder-side sealing ring 29 into the annular cylinder space 31, so that a proper supply for the pressure medium is possible even when the piston 15 is fully extended.

The design according to the invention also has a particular advantage in terms of construction in that no particularly dimensioned spoilings are required. In the case of screw connections, the outer cylinder sleeve would have to have a substantially larger cross section and the other parts would also have to be correspondingly larger. In the embodiment according to the invention, it is possible to connect the conical ring 14 or the component 36 forming the pipe section 21 and the base 19 to one another without screwing. Grooves 37 are provided in the cylinder sleeve, into which locking rings 37 'engage. These locking rings have an L-shaped cross section, one leg abutting the wall of the cylinder sleeve 20 and the other leg engaging in the groove 37 on the same. In order to be able to introduce these locking rings 37 'into the grooves 37, they are severed once or several times in their scope. Especially then if only one separating point is provided, the separating surfaces of the locking rings run at an acute angle to a radial plane of the locking ring 37 ', in order to thereby enable insertion. Furthermore, it is also provided that the component 36 and the conical ring 14 are preferably offset at their outer edge regions over a length which corresponds to the leg of the locking ring 37 'resting on the cylinder sleeve by the thickness of this leg.

In the final state, the two legs of the locking ring 37 'are clamped between the cylinder sleeve 20 and the cone ring 14 or the component 36, so that only shear forces can occur under load, but no bending forces, as is the case, for example, when a circlip is inserted Would be the case. Furthermore, with such an embodiment, a level closure of all parts to be connected to one another can be made possible, and the load limits are also very high. Of course, such an assembly with the locking rings 37 'according to the invention can only take place if the components to be locked (retaining ring 14 and component 36) can initially be pushed correspondingly far into a cylinder sleeve 20 so that the locking ring 57' into the groove 37 can be inserted. The corresponding component is then again pulled outwards until it rests on the locking ring 37 '. These measures create a much more resilient connection than would be possible with individual screws. This enables a construction with very small dimensions.

In the present invention, an adjustable switching device for switching an e-hydraulic valve also engages in the displacement area of the piston 15. This makes it possible, depending on the closed state of the jaws 2 and thus in the position of the exactly calculable Piston 15 fine valve switching to make so that the device works automatically. The piston surface 18 is thus acted upon up to the required pressing diameter, whereupon the hydraulic valve is switched over after a previously adjustable displacement away from the piston 15, so that the annular space 31 is then acted upon and causes the piston 15 to return to the rest position.

In a special exemplary embodiment it is provided that a control rod 38 engages in the displacement area of the piston 15, which can be brought into operative connection with a stop 40 ', the distance of which from the piston end on the clamping jaw side can be adjusted. In a structurally simple manner, this control rod 38 is guided displaceably in a bore 39 of the fixed cone ring 14. The switchover can take place by mechanical transmission or also by electrical switching means. A simple embodiment can be seen in FIG. 3. By means of an adjusting knob 6, which is arranged on a threaded bolt 40, the stop 40 'for the control rod 38 can be adjusted in the axial direction, so that, depending on the desired end diameter, the piston 15 sooner or later abuts the free end of the control rod 38 and thus the stop 40 'shifted. becomes. It is also possible to provide a scale 41 with a corresponding display element in order to make the adjustment visible from the outside. In this context, it is also expedient if a fine adjustment is possible, which can be regulated as a function of the thread pitch of the threaded bolt 40, so that, for example, with a corresponding thread pitch it is achieved that the compression diameter is changed by 1 mm when the adjusting knob is turned .

3 can be a mechanical transmission of this switching tion can be removed. When the control rod 38 moves, a control element 43 with an inclined run-up surface 44 is moved in the direction of the arrow 45 after the free end of the iόlbens 15 abuts. The bevel 46 on an actuating rod 47 can move it in the direction of arrow 48. This actuation rod 47 is operatively connected to the actuation handle 7 or the connecting rod 49 connected thereto. This connecting rod 49 leads to a lever 50, which causes the switching of the hydraulic valve 51. The actuating rod 47 engages in one

Recess 60 in the bolt 52 of the connecting rod 49 and thus locks this connecting rod 49 in a position in which the hydraulic valve 51 is switched to the feed position for the piston 15. After a corresponding return of the actuating rod 47 in the direction of arrow 48, the bolt 52 is released, so that the lever 50 and / or the spring 50 and thus also the connecting rod 49 are moved in the direction of the arrow 54 by the optionally spring-loaded hydraulic valve 51 and / or a spring 61.

As soon as the operating handle 7 is again pressed against the direction of the arrow 54 for a new operation or, for example, is pulled by a magnet, the operating rod 47 can in turn return to the position shown in FIG. 3, so that the connecting rod 49 or the bolt 52 in turn fixes the same becomes. As a result, due to the action of the spring 62, the threaded bolt 40 and thus the stop 40 'are brought back into their position shown in FIG. 3. The actuating rod 47 is locked again. Of course, the control rod 35 could also be designed to be spring-loaded, so that it rests against the stop 40 'in its rest position.

A particular advantage of the configuration according to the invention lies in the relatively short overall length of the device, which is achieved by the special design of the double-acting piston. This eliminates the essential structural lengths, which are given, for example, by springs which are intended to cause a piston to be returned. The return can also be carried out hydraulically in a simple manner according to the invention, so that these additional components can be omitted.

Instead of the arrangement of an annular cylinder, it would also be conceivable to omit the inner pipe section 21 of the component 36, in which case a corresponding pipe section 21 would be fixedly connected to the piston 15 or would be designed in one piece with the latter. Such an extension of the piston would then have to project beyond the base 19 of the component 36 in the axial direction of the piston, since in such an embodiment the tube piece 21 forming part of the piston 15 must form the inner cylinder wall. It is then still necessary to provide a corresponding seal between the remaining component 36 and the one-piece pipe section 21 connected to the piston 15. However, the configuration explained in the above description, in which all specially machined parts of the device are covered and are therefore protected against damage, is considerably cheaper.

The device according to the invention also has a particular advantage in that the piston 15 can be moved relatively easily as long as no pipe connection has yet been pressed. This is very easy because there are no special opposing forces. This has made it possible to seal the storage tank for the pressure medium, which will generally be oil, in an airtight manner, so that a pressure can be built up within the storage tank. It is sufficient if in the free space of the Ratstankes compressed air is introduced so that the actual pressure medium is preloaded. There is therefore the possibility, without actuating a pump, to supply the pressure medium solely through the pressure built up in the storage tank via the supply line 34, so that the piston 15 up to that starting position, in which it comes into contact with the parts to be pressed, in one Overdrive is advanced. The workflow can thereby be significantly accelerated, so that no additional measures for reducing the piston travel are required, depending on the size of the parts to be pressed. This fast forward gear, which is only possible due to the smooth running of the embodiment according to the invention, means that there are no additional means here which are intended to limit the return movement of the piston.

It can be seen precisely from the section according to FIG. 2 that the device according to the invention is practically fault-free and therefore also maintenance-free. The parts in which there is a risk of damage are covered entirely or are not accessible from the outside when the parts to be pressed are inserted. It is thus also a very simple handling of this device. The construction is simple and, despite achievable high pressures, can be carried out in a relatively small dimension, so that the device becomes very light and therefore also easy to transport. Of course, the simple construction also results in an inexpensive construction.

Claims

Patent claims:

1. Apparatus for pressing tubular parts, in particular for pressing or pressing pipe connectors onto pipes, sleeves or hoses, consisting of several, adjustable in the radial direction, spring-loaded clamping jaws and a piston acting on the clamping jaws, which is annular in cross section and which is designed to the end region facing the clamping jaws is widened conically on its inside, the clamping jaws with their radially outer loading boundary surfaces bearing on the conical extension with a corresponding angle of inclination, and the piston being hydraulically displaceable in the direction of the clamping jaws and returnable to its rest position, characterized in that that the effective piston surface (25) for the return of the double-acting piston (15) is only a fraction of the piston surface (18) for the feed thereof, that the jaws (2) facing away from the end of the piston (15) in an annular n hydraulic cylinder (17) engages and that the effective piston surface (18) for advancing the piston (15) is formed at the free end of the same, facing away from the clamping jaws (2), and runs parallel to the bottom (19) of the annular cylinder (17), wherein the piston has the largest cross-sectional area at its effective piston surface (18) forming the feed end.

2. Apparatus according to claim 1, characterized in that the annular cylinder (17) is formed by an outer cylinder sleeve (20) and a coaxially inserted pipe section (21), the cylinder base (19) integrally connected to the inserted pipe section (21) .

3. Device according to claims 1 and 2, characterized in that the piston (15). its end facing away from the clamping jaws (2) has a circumferential collar (22) of larger diameter at least at its outer boundary, the outer boundary (23) of the cylinder (17) at least over the sliding range of the collar (22) having an outer diameter of the collar (22) has a correspondingly enlarged inner diameter.

4. Device according to claims 1 and 3, characterized in that the effective piston surface (18) for the advance of the piston (15) facing away from the federal government (22), the effective piston surface (25) for the return of the piston (15th ), the annular cylinder space (31) being formed by the piston outer surface (24), the inner boundary (23) of the outer cylinder sleeve (20), the piston surface (25) and the end surface of the enlarged region with a larger diameter.

5. Apparatus according to claim 1 and one of the preceding claims, characterized in that a groove-like depression or bevel (33, 32) are provided on the outer edge of the cylinder base (19) and on the outer edge region of the piston surface effective for the feed (18) which together form a circumferential ring channel when the piston (15) is at rest, the supply line (34) for the pressure medium opening in the area of the ring channel.

6. The device according to claim 1 and one of the preceding claims, characterized in that axially the same as the piston (15) at the other free end of the outer cylinder sleeve Zy (20), a cone ring (14) is fixed, the inner limit (12) towards the piston is expanded conically, the outer limits of the clamping Bake in a known manner, taper conically towards both ends when viewed in the axial direction.

7. The device according to claim 1 and one of the preceding claims, characterized in that formed from the pipe section (21) and the cylinder base (19)

Component (36) and the conical ring (14) at the two ends of the outer cylinder sleeve (20) are fixed to the cylinder sleeve (20) by locking rings (37 ') engaging in grooves (37) in the cylinder sleeve (20).

8. The device according to claim 7, characterized in that the locking rings (37 ') have an L-shaped cross section, wherein one leg rests on the inner wall of the cylinder sleeve (20) and the other leg in the groove (37) the same intervenes.

9. Device according to claims 7 and 8, characterized in that the locking rings (37 ') in their order direction are severed once or several times, the parting surfaces of the locking rings (37') at an acute angle to an Rs .dialplane of the locking ring (37 ').

10. Device according to claims 7 to 9, characterized in that the component (36) and the conical ring (14) at their outer edge regions preferably over a length which the leg of the locking ring (37 ') corresponds to the thickness of this leg.

11. The device according to claim 1, characterized in that in the displacement region of the piston (15) engages in a known manner adjustable switching device for switching th a hydraulic valve (51).

12. The device according to the preceding claims, characterized in that the storage tank of the hydraulic medium is sealed airtight and can be connected to a compressed air line.