EP3199259B1 - Telescopic support and outer tube of a telescopic support - Google Patents

Description

The invention relates to an outer tube of a telescopic support and a telescopic support with a thin-walled pipe section.

In the construction sector, telescopic supports are used for a variety of supporting tasks, for example as ceiling or erection supports for supporting concrete formwork. The telescopic supports have an outer tube and an inner tube axially displaceable relative to the outer tube. The outer tube may have a thread on which the inner tube is indirectly or directly supported. The thread of the outer tube is usually an external thread. Such telescopic supports are for example from the DE 10 2009 054 628 A1 known.

The document JP S57 47662 U discloses an outer tube for a telescopic support with the features of the introductory part of claim 1.

The outer tubes of the telescopic supports used are usually galvanized steel tubes. On the galvanized steel tubes, the thread can be rolled up.

In order to reduce the weight of the outer tubes with constant load capacity, outer tubes are used with the largest possible outer diameter and low wall thickness.

In the production of such outer tubes, however, it has been found that it is difficult to roll a thread on the outer tubes. The coiled threads do not have the necessary stability to accommodate the load transferred to the thread. For example, it has been observed in tests that a nut screwed onto an external thread of an outer tube "slips" on the external thread. In other cases, the thread is torn off when rolled up. This is due, on the one hand, to the low wall thicknesses of the tubes used and, on the other hand, to the tolerances in the roundness of the tube cross section and the outside diameter of the tube.

The problem can be remedied by welding a finished threaded piece onto a thread-free outer tube. However, the resulting weld can be a weak point of the telescopic support. Furthermore, the weld must be post-treated to ensure adequate corrosion protection.

Object of the present invention is therefore to provide an improved outer tube of a telescopic support and a telescopic support with such an outer tube.

This object is achieved by an outer tube according to claim 1 and a telescopic support according to claim 3. The dependent claims give preferred developments again.

1. a) Aufschieben eines Rings auf den Rohrabschnitt, wobei der Innendurchmesser des Rings dem Außendurchmesser des Rohrabschnittes entspricht,
2. b) Einschieben eines Stempels in den Rohrabschnitt, wobei der Außendurchmesser des Stempels größer ist als der Innendurchmesser des Rohrabschnittes, sodass der Rohrabschnitt aufgeweitet wird,
3. c) Herausziehen des Stempels aus dem Rohrabschnitt,
4. d) Überziehen des aufgeweiteten Rohrabschnitts mit dem Ring, sodass der aufgeweitete Rohrabschnitt wieder auf seinen ursprünglichen Außendurchmesser verjüngt wird,

wobei Schritt d) nach Schritt c) oder gleichzeitig mit Schritt c) durchgeführt wird.A pipe section of an outer tube of a telescopic support for the construction sector can be consolidated and calibrated with the following steps:

1. a) pushing on a ring on the pipe section, wherein the inner diameter of the ring corresponds to the outer diameter of the pipe section,
2. b) inserting a stamp into the pipe section, wherein the outer diameter of the stamp is greater than the inner diameter of the pipe section, so that the pipe section is widened,
3. c) pulling the stamp out of the pipe section,
4. d) coating the expanded pipe section with the ring so that the expanded pipe section is rejuvenated to its original outer diameter,

wherein step d) is performed after step c) or simultaneously with step c).

As a result, an end portion of a tube can be solidified and calibrated in a simple manner, wherein the tube used can remain permanently clamped on one side during the implementation of the method. Step b) is carried out after step a) or simultaneously with step a). Steps c) and d) are carried out after steps a) and b).

The method is applied to an end pipe section.

The stamp is only partially inserted into a pipe section and pulled out again. Particularly preferably, the stamp is inserted about 300mm into the tube.

The tube used in the method is thus expanded by a punch or mandrel, which is inserted from the inside into the tube. When expanding the pipe section, the pipe is preferably expanded by about 1mm, i. The outer diameter increases by the expansion by about 1mm. When expanding the tube creates a structural change that causes a consolidation of the expanded pipe section. Furthermore, by inserting the stamp, a calibration of the inner diameter of the expanded pipe section. The inner diameter of the pipe section is thereby formed on the outer diameter of the punch.

In order to facilitate the insertion of the stamp, a punch can be used, which has a first bevel or rounding between its first entering the pipe front and its voltage applied to the inside of the pipe section outside.

Furthermore, the extraction of the punch from the tube can be facilitated if a punch is used, which has a second bevel or rounding between its voltage applied to the inside of the pipe section outside and its front side opposite the rear side.

The insertion of the stamp is preferably carried out at room temperature, so that a cold deformation or cold forming of the expanded pipe section takes place.

A further consolidation of the tube and a calibration of the outer diameter of the treated in the process pipe section takes place in that after the expansion of the pipe section, the tube is at least partially covered by the ring whose inner diameter is smaller than the outer diameter of the expanded pipe section. The expanded pipe section is thereby tapered by the inside of the ring, which is pulled over the expanded pipe section. In this case, a structural change of the tapered pipe section takes place. Due to the calibrated outer diameter, an external thread can be applied to the pipe particularly well.

The drawing of the ring over the outside of the expanded pipe section is preferably carried out at room temperature, so that a cold deformation of the now tapered pipe section takes place.

It is used a ring whose inner diameter substantially corresponds to the outer diameter of the pipe section before expansion by the punch. As a result, as a result, a pipe or pipe section can be produced, the outer diameter of which, after carrying out the method, corresponds to the outer diameter before the method is carried out. If the method is performed on only one pipe section, then a pipe of constant outside diameter can be obtained on the treated and untreated pipe sections of the pipe. At the same time, however, the treated pipe section is solidified and its outer diameter is calibrated or the roundness is improved.

The tolerance of the outer diameter can be improved from typically ± 0.3mm to ± 0.15mm.

1. a) Aufschieben des Rings auf das Rohr;
2. b) Einschieben des Stempels in das Rohr, wobei ein Rohrabschnitt aufgeweitet wird;
3. c) Herausziehen des Stempels aus dem Rohr;
4. d) Überziehen des aufgeweiteten Rohrabschnittes mit dem Ring, wobei der aufgeweitete Rohrabschnitt wieder verjüngt wird.

The process is carried out particularly easily on the pipe, since the ring is pushed onto the pipe before the insertion of the stamp and the stamp is pulled out of the pipe after it has been inserted into the pipe. The method thus has the following steps:

1. a) pushing the ring onto the pipe;
2. b) inserting the stamp in the tube, wherein a pipe section is widened;
3. c) pulling the punch out of the tube;
4. d) coating the flared pipe section with the ring, wherein the expanded pipe section is rejuvenated.

The punch and the ring are preferably guided at a fixed distance from each other. In this way, a device for carrying out the method can be constructed structurally simple. Stamp and ring can be arranged, for example, on a common bracket. Alternatively, punch and ring may be integrally formed. The ring is preferably performed about 20mm in front of the stamp.

A thread is applied to the consolidated and calibrated tube section. The thread is, especially in the form of an external thread, rolled up. As a result, the treated pipe can be used as the outer tube of a telescopic support in the construction sector.

On the treated pipe section is particularly preferably a thread in the form of a trapezoidal thread with a flank angle of less than 15 °, in particular 10 °, rolled. Due to the small flank angle, a very high load can be transferred to the thread.

To carry out the method, a tube in the form of a galvanized steel tube can be used. After carrying out the method, such a pipe has at least one treated pipe section with a high one Stability, dimensional stability and corrosion resistance. Galvanized steel tubes are manufactured in standardized quantities in large quantities and can be obtained inexpensively.

Disclosed is thus a method for producing an outer tube of a telescopic support for the construction sector, wherein at least one pipe section of the outer tube is treated by a method described above.

Disclosed is also an apparatus for carrying out a method described above, with a clamping device for firmly receiving a tube, a cross-sectionally round stamp which can be pressed into the tube in the longitudinal direction of a clamped tube and a ring in the longitudinal direction of the clamped tube on the Outer side of the tube is drawable affect.

Preferably, the ring has - except for one or two end chamfers - a constant inner diameter. As a result, the ring is structurally simple and inexpensive to produce and also allows the production of a particularly high quality outer surface of the machined pipe section.

The punch is preferably movable together with the ring along the longitudinal axis of a clamped tube. This can be a Control of the process carried out with the device can be simplified.

In a particularly preferred embodiment of the invention, the stamp is connected to the ring. The device is structurally particularly simple executable. Preferably, the connection between the punch and ring is immediate and rigid.

The invention relates to an outer tube of a telescopic support for the construction sector according to claim 1.

One-piece outer tubes of telescopic posts with a continuous outer diameter and such a large outer diameter to wall thickness ratio are both very light and extremely stable. The production of such outer tubes takes place at least partially by the method described above.

The outer tube is preferably made of galvanized steel. Galvanized steel is corrosion resistant, stable and comparatively inexpensive.

In a particularly preferred embodiment of the invention, the outer diameter of the outer tube is greater than 60.3mm, ie it is suitable for loads over 30kN. The outer tube is characterized particularly stable and lightweight. The cross-sectional area of the outer tube is preferably always greater than 419 mm ² .

Finally, the invention relates to a telescopic support for the construction sector with a previously described outer tube and an inner tube slidably disposed therein.

In the telescopic support according to the invention, a stop element according to the invention may be provided in the region of one end of the outer tube, wherein the stop element at least partially obscures the free cross-sectional area of the outer tube. Covering the cross-sectional area in the present application also means an at least partial projection of the stop element into the clear cross-section of the outer tube. The advantage consists essentially in the fact that the stop element can be easily arranged on the outer tube, without the need for a complex change of the inner cross section of the outer tube or a welding of separate pipe sections is required. Depending on the selected type of fastening, a robust pull-out limiter of the inner tube, which is highly load-bearing against axially acting forces, can be realized. The stop element is preferably attached according to the invention without separate connection means on the outer tube and arranged in the simplest case only in a press fit on or in the outer tube. However, the stop element can also be arranged in the sense of a snap ring in a groove arranged on the outer tube or via a latching connection or a bayonet-type fastening to the outer tube. The stop element is connected to the outer tube and this in the region of the free end of the outer tube.

According to a preferred embodiment of the invention, the stop element engages in a arranged on a lateral surface of the outer tube inner and / or outer thread of the outer tube, wherein a particularly resilient arrangement of the stop element thereby is achieved, that the stop element engages with an outer and / or an internal thread into or into the corresponding thread of the outer tube.

In order to secure the stop element against unintentional release from its mounting position, it has proven to be advantageous in practice that the stop element is assigned a Ausdrehsicherung. The Ausdrehsicherung may in particular have a arranged on the stop element and einschlagbare in the thread of the outer tube locking tab. The stop element, here an impact flap, engages in a passage opening of the outer tube.

The load capacity of the stop member against axial loads, as may occur in particular when a soiled inner tube is pushed into the outer tube, is further improved in that the stop element has an end face, i. an end wall portion, the one end of the outer tube at least partially covered.

The stop element is preferably formed according to an embodiment of the invention as a cap or as a sleeve. As a result, on the one hand penetration of impurities, such as fresh concrete, can be counteracted in the interior of the outer tube, which is favorable for a low-maintenance and reliable function. On the other hand, the stop element thereby serve as a (sliding) bearing and at the same time as a stripping element for a contaminated inner tube. If the stop element is designed as a cap or as a sleeve, no additional processing must be carried out to create a stop element on the outer tube.

For the purpose of a function of the failsafe independent of the orientation of the inner tube in the outer tube of the stop means of the inner tube is preferably formed as a flared, for example crimped, end of the inner tube. As a result, the inner tube can not be removed from the outer tube even with very large forces acting on it, as can occur in practice.

So that the stop element can not be released from its mounted position even under high bending moments of the extended inner tube, the inner tube according to a development of the invention at least one radially over its outer circumferential surface laterally projecting projection of the flared end of the inner tube, the stop means, axially spaced apart. The projection is preferably formed integrally with the inner tube and made in particular via a forming process on the inner tube. The projection is advantageously formed in the form of a nub or a bead projection and may extend in the circumferential direction of the inner tube over a preferably large circumferential angle. According to one embodiment of the invention, a plurality of projections may be provided, which are lined up along the outer circumference of the inner tube spaced from each other and which are preferably arranged in a plane orthogonal to the longitudinal axis of the inner tube.

The inner tube is axially guided for the purpose of improved positioning accuracy and reliable support behavior on the stop element and / or on an inner circumferential surface of the outer tube, preferably in sliding play positive engagement. Here, the inner tube on the inner circumferential surface of the outer tube is expedient manner with the one stop means, here for example with the flared edge of his arranged in the outer tube end, and / or out with the at least one projection.

The trained preferably as a cap stop element has, according to a particularly preferred manufacturing aspects of the invention an internal thread which engages in an external thread of the outer tube, wherein the external thread is additionally engaged with an internal thread of a lowering nut on which a transverse to the longitudinal axis of the telescopic support can be supported by the outer and inner tube feasible securing bolt. As a result, on the one hand a fine adjustment of the overall functional length of the telescopic support and a simplified stripping possible, on the other hand, the stop element can be screwed directly onto an already provided thread. The stop element acts at the same time in the sense of a lock nut or a stop element for the lowering nut, so that it is arranged captive on the telescopic support.

Overall, the described prop (telescopic support) has the advantage that it is easy to assemble (final assembly). The outer and inner tube can be edited and manufactured without additional elements and only when joining the outer and inner tube is the Lowering nut with the connected elements screwed onto the outer tube. Also, the fuse pin is attached to the outer tube prior to assembly of the inner tube with the outer tube. If the prop is assembled according to the invention, the securing bolt can only be used in the region of the insertion opening, provided that the stop element has an outer diameter which is greater than the inside diameter of a portion of the correspondingly shaped securing bolt comprising the outer tube.

Further features and advantages of the invention will become apparent from the following detailed description of an embodiment of the invention, with reference to the figures of the drawing, which shows essential to the invention and from the claims.

The features illustrated in the drawing are not necessarily to scale and illustrated in such a way that the features of the invention can be made clearly visible. The various features may be implemented individually for themselves or for a plurality of combinations in variants of the invention.

In the schematic drawing an embodiment of a telescopic support according to the invention with an outer tube according to the invention and a part of the manufacturing process of the outer tube is shown and explained in more detail in the following description.

Fig. 1

eine perspektivische Ansicht einer ausschnittsweise dargestellten erfindungsgemäßen Teleskopstütze mit einem Außenrohr und einem als Kappe ausgebildeten Anschlagselement;

Fig. 2

ausschnittsweise einen Längsschnitt durch eine der Fig. 1 entsprechende Teleskopstütze;

Fig. 3

eine perspektivische Ansicht der Kappe aus Fig. 1;

Fig. 4

eine Schnittdarstellung der in Fig. 3 gezeigten Kappe;

Fig. 5

die Einzelteile der erfindungsgemäßen Teleskopstütze vor dem Zusammenfügen des Innenrohrs mit dem Außenrohr; und

Fig. 6a

eine geschnittene Seitenansicht einer Vorrichtung zur Herstellung des Außenrohrs in einer ersten Stellung;

Fig. 6b

die Vorrichtung zur Herstellung des Außenrohrs in einer zweiten Stellung;

Fig. 6c

die Vorrichtung zur Herstellung des Außenrohrs in einer dritten Stellung;

Fig. 6d

die Vorrichtung zur Herstellung des Außenrohrs in einer vierten Stellung;

Fig. 6e

das Außenrohr aus Fig. 6d mit einem Gewinde; und

Fig. 6f

einen Ausschnitt aus Fig. 6e.

Show it:

Fig. 1

a perspective view of a fragmentary telescopic support according to the invention shown an outer tube and a stopper member formed as a cap;

Fig. 2

partially a longitudinal section through one of Fig. 1 corresponding telescopic support;

Fig. 3

a perspective view of the cap Fig. 1 ;

Fig. 4

a sectional view of in Fig. 3 shown cap;

Fig. 5

the items of the telescopic support according to the invention prior to assembly of the inner tube with the outer tube; and

Fig. 6a

a sectional side view of an apparatus for producing the outer tube in a first position;

Fig. 6b

the device for producing the outer tube in a second position;

Fig. 6c

the device for producing the outer tube in a third position;

Fig. 6d

the device for producing the outer tube in a fourth position;

Fig. 6e

the outer tube off Fig. 6d with a thread; and

Fig. 6f

a section from Fig. 6e ,

In Fig. 1 is a generally designated 10 telescopic support according to the invention for the construction sector in a selected column section reproduced. The telescopic support 10 has an outer tube 12 according to the invention and an inner tube 14 arranged axially displaceably therein. The inner tube 14 has at its in the figure above shown free end 16 a known support plate 18, while the outer tube 12 has a foot plate for secure positioning on a respective substrate at its not shown in detail in Fig. Foot end.

At a head end, i. the support plate 18 of the inner tube 14 facing the end 20 of the outer tube 12, a cap 22 is arranged, which serves as a stop element for the inner tube 14 and by the axial removal or a failure of the inner tube 14 is prevented from the outer tube 12.

The cap 22 is formed in a manner corresponding to a cap nut and has a substantially cylindrical wall portion 24 with an internal thread 26. Adjoining the cylindrical wall section 24 is an edge region 28 of the cap 22 which is arranged above the cylindrical wall section 24 and which is angled radially in the direction of a cylindrical longitudinal axis 30 of the telescopic support 10 and which has a free cross-sectional surface 32 the outer tube 12 partially covered.

The cap 22 and its internal thread 26 is in engagement with a arranged on the outer surface 34 of the outer tube 12 external thread 36. In the external thread 36 of the outer tube 12 also engages a so-called lowering nut 38, to which a handle 38 'is pivotally mounted and by twisting around the Longitudinal axis 30 of the telescopic support 10 is axially movable on the outer tube 12 along.

At the lowering nut 38 is a transversely to the longitudinal axis 30 of the telescopic support 10 through the outer and inner tube 12, 14 plugged securing bolt 40 is supported. The outer tube 12 has in this respect two opposite and parallel to the longitudinal axis 30 of the telescopic support 10 elongated first through openings (slots) 42, while the inner tube 14 has a plurality of circular opposing (aligned) second through-openings 44 which along the inner tube 14 in each case Periodically under or over each other are arranged.

For approximate length adjustment of the telescopic support 10, the inner tube 14 is first pulled out to a desired length of the telescopic support 10 and the locking bolt 40 subsequently inserted through the first through-insertion openings 42 of the outer tube and with these each aligned second insertion openings 44 of the inner tube 14.

By rotating the lowering nut 38 arranged below the securing bolt 40 in FIG. 1, its relative position along the outer pipe 12 can be subsequently changed steplessly. As a result, at the same time the axial support position of the securing bolt 40 on the outer tube 12 and the coupled thereto with the inner tube 14 along the outer tube 12, i. the length of the telescopic support 10, be fine-tuned as needed.

As in particular from the Fig. 2 , A shown over a portion of the telescopic support 10 longitudinal section, shows the cap covers 22 with its angled edge region an end face 46 of an end 20 of the outer tube 12. The inner tube 14 has a trained as a flared end stop means 48, which for the purpose of fail-safe of the inner tube 14 from the outer tube 12 to the cap 22 and at its angled edge portion 28 can be brought into abutment, provided no further securing elements are effective.

The inner tube 14 additionally has a plurality of knob-like projections 50, which are arranged at a distance from the stop means (widened end) 48 of the inner tube 14 and project laterally radially beyond an outer lateral surface 34 'of the inner tube 14. The knob-like projections 50 are brought into contact with the cap 22 upon reaching a predetermined maximum extension of the inner tube 14 and thus enforce a remaining in the outer tube 12 minimum length of the inner tube 14. When bending moments occur, the inner tube 14 is therefore supported on an inner circumferential surface 52 of the outer tube 12th from, whereby a levering of the cap 22 is reliably avoided by the outer tube 12.

The knob-like projections 50 have a function as the stop means 48 and limit the Teleskopierlänge the telescopic support.

The internal thread 26 of the cap 22 is, as in the FIGS. 3 and 4 is shown in more detail, designed as a flat profile and has a thread profile 54 interrupted along the thread.

From the representation in the Fig. 4 It can be seen that on the cylindrical cap portion 24 of the cap 22 is designed as a turn-tab Aufrehsicherung 56 is arranged, which after screwing the cap on the external thread 36 (FIGS. Fig. 1 and 2 ) of the outer tube 12 is hammered into the external thread 36 of the outer tube 12 and located in an opening 57 (see Fig. 5 ) festkrallt in the external thread 36 of the outer tube 12.

In the Fig. 5 the individual parts of the telescopic support 10 according to the invention are shown prior to assembly of the inner tube 14 with the outer tube 12. On the inner tube 14, the above-explained support plate 18 is already welded, while at the foot-side end of the outer tube 12, a foot plate 58 is welded. The lowering nut 38 is screwed onto the external thread 36 of the outer tube 12, while the cap 22 is pushed onto the inner tube 14 and secured by the knob-like projections 50 and the support plate 18 against axial removal from the inner tube 14. To assemble the inner tube 14 with the outer tube 12, the inner tube 14 with its flared end 48 (stopper) as far as inserted axially into the outer tube 12 at the head end 20 of the outer tube 12 until at least the knob-like projections 50 come to rest within the outer tube 12 , Subsequently, the cap 22 is screwed onto the external thread 36 of the outer tube 12 and the Einschlaglasche 56 taken with a tool in the opening 57 of the outer tube 12.

Fig. 6a shows a sectional side view of an apparatus 60 for carrying out a method for producing the outer tube 12. The device 60 is shown in a first position. The device 60 is shown greatly simplified and schematically. Guides, drives and the like of the device 60 have not been shown for reasons of clarity.

The outer tube 12 is in Fig. 6a in an untreated condition. In the outer tube 12 may be a galvanized steel tube with a Outer diameter of over 71mm, 76.5mm, 83mm or 83.5mm, and a wall thickness of 2.6mm act. The outer tube is clamped on the right in a tensioning device (not shown) of the device 60.

The external thread 36 (see Fig. 1 . 2 . 5 ) of the outer tube 12 could be in the in Fig. 6a shown state of the outer tube 12 are not rolled up, since the ratio of outer diameter to wall thickness and the tolerance of the outer diameter of the outer tube for this purpose in the case of the stated outer diameter and wall thicknesses is too large. The outer tube 12 is therefore in the inventive method, which in the Fig. 6a-6d is solidified in the region of the deformation and calibrated the outer diameter, that is, the tolerance of the outer diameter is reduced.

The device 60 has this according to Fig. 6a a punch 62 and a ring 64. The punch 62 and the ring 64 are rotationally symmetrical to the dash-dotted line longitudinal axis of the outer tube 12 is formed. The inner diameter of the inner lateral surface 66 of the ring 64 corresponds to the calibrated outer diameter, ie the outer diameter of the outer tube 12 to be achieved. Furthermore, the inner lateral surface 66 of the ring 64 is circular in shape in order to achieve improved roundness of the outer circumferential surface of the outer tube 12.

The ring 64 has a first rounding 68 and a second rounding 70 in order to be able to be guided better over the outer tube 12.

Fig. 6b shows the device 60 in a second position. The punch 62 and the ring 64 are shifted together in this illustration to the right. Here, the punch 62 is connected to the ring 64. The Connection between the punch 62 and the ring 64 is in the illustrations of Fig. 6a-6d not shown for reasons of clarity. The inner diameter of the ring 64 substantially corresponds to the outer diameter of the untreated outer tube 12. The ring 64 can therefore be pushed onto the outer tube 12 with little effort.

Fig. 6c shows the device 60 in a third position. The punch 62 is inserted under force in sections in the outer tube 12. To facilitate the insertion of the punch 62, this has a third rounding 72. With far in the outer tube 12 retracted punch 62 allows a fourth rounding 74 a slight extension of the outer tube 12 (not shown). By retracting the punch 62, the outer tube 12 is widened in a first tube section 76 by cold forming. The first pipe section 76 is thus somewhat longer and the wall thickness in the first pipe section 76 somewhat smaller.

Fig. 6d shows the device 60 in a fourth position. The punch 62 has been moved together with the ring 64 to the left of the outer tube 12 away. The ring 64 was pulled under force over the expanded first pipe section 76. The outer diameter of the expanded first tube section 76 was thereby restored to the original outer diameter of the tube 12 according to Fig. 6a rejuvenated. The roundness and tolerance of the outer diameter was improved. The taper further causes a cold forming of the first pipe section 76. In this way, a further solidification of the first pipe section 76 is achieved. The wall thickness of the first pipe section 76 has been reduced, whereby the length of the outer pipe 12 has been increased.

The device 60 in FIG Fig. 6d is in the same position as in Fig. 6a , The Fig. 6a-6d therefore show a complete cycle of the method described above. Such a cycle lasts about 8 seconds, with the punch 62 being introduced into the tube section 76 by about 300 mm.

By treating the first pipe section 76, the external thread 36 can now be easily rolled onto this first pipe section 76.

Fig. 6e shows the outer tube 12, wherein the first tube section 76 has the external thread 36. The external thread 36 was rolled up onto the first pipe section 76. In Fig. 6e a section 78 of the external thread 36 is marked.

Fig. 6f shows the cutout 78 of the external thread 36 Fig. 6e , Out Fig. 6f it can be seen that the external thread 36 has a flank angle F. The flank angle F is 10 ° (for illustrative purposes, a larger angle is shown in the drawing). Due to the small flank angle of less than 15 ° less inward radial forces must be absorbed by the outer tube 12 under load of the external thread 36.

In summary, the invention relates to an outer tube of a telescopic support and the telescopic support and the outer tube contained therein. The outer tube can be made of weight and stability reasons of a standard galvanized steel tube with a large outer diameter and low wall thickness. A tube section of the outer tube can be widened in a method with a stamp and then rejuvenated with a ring to the original outer diameter. This can be a solidification of the pipe section and calibration of the Outer diameter of the pipe section can be achieved. An external thread will be rolled up on the pipe section.

Claims (3)

1. Outer tube (12) for a telescopic support (10) for the construction industry, the outer tube (12) being designed to be integral and to have a continuous outer diameter and having a first end tube portion (76) and a further tube portion, and having an external thread (36) rolled onto its outer lateral surface of the end tube portion (76) of the outer tube, characterized in that the ratio of the outer diameter of the outer tube (12) to the wall thickness of the further tube portion of the outer tube (12) is greater than 26.2, the outer tube (12) having a wall thickness in the region of the external thread (36) of the end tube portion (76) that is reduced in comparison with the wall thickness of the outer tube (12) of the further tube portion.
2. Outer tube according to claim 1, characterized in that the outer diameter of the outer tube (12) is greater than 60.3 mm.
3. Telescopic support (10) for the construction industry, comprising an outer tube (12) according to either claim 1 or claim 2 and an inner tube (14) that is arranged so as to be axially moveable therein.

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