Method for reinforcing and calibrating a pipe portion

Abstract

A method and a device for producing an outer pipe of a telescope-like support, for reasons of weight and stability, is produced from a standardized zinc-coated steel pipe having a large outer diameter and a small wall thickness. Also included is the telescope-like support and the outer pipe which is contained therein. A pipe portion of the outer pipe is expanded in the method with a punch and subsequently tapered to the original outer diameter again with a ring. A reinforcement of the pipe portion and a calibration of the outer diameter of the pipe portion are thereby achieved. An outer thread can be rolled on the pipe portion.

Claims

1. A method for reinforcing and calibrating of at least a thin-walled pipe portion of an outer pipe of a telescope-like support for the construction sector, comprises the steps of: a) pushing a ring onto the pipe portion, whereby the inner diameter of the ring corresponds to the outer diameter of the pipe portion; b) inserting a punch into the pipe portion, the outer diameter of the punch being greater than the inner diameter of the pipe portion thus expanding the pipe portion; c) pulling the punch out of the pipe portion; d) covering the expanded pipe portion with the ring, thus tapering the expanded pipe portion; wherein step d) is performed after step c) or simultaneously with step c); and e) rolling a thread in the form of a trapezoidal thread having a flank angle of less than 15 at least partially on the pipe portion.

2. The method according to claim 1, wherein the punch and the ring are guided with fixed spacing with respect to each other.

3. The method according to claim 1, wherein the outer pipe in the form of a zinc-coated steel pipe is used to carry out the method.

4. The method according to claim 1, wherein the outer pipe having an outer diameter of more than 60 mm and a wall thickness of less than 3 mm is used to carry out the method.

5. The method according to claim 1, wherein the outer pipe having an outer diameter of more than 60 mm and a wall thickness of less than 2.7 mm is used to carry out the method.

6. A method for reinforcing and calibrating of at least a thin-walled pipe portion of an outer pipe of a telescope-like support for the construction sector, comprises the steps of: a) pushing a ring onto the pipe portion, whereby the inner diameter of the ring corresponds to the outer diameter of the pipe portion; b) inserting a punch into the pipe portion, the outer diameter of the punch being greater than the inner diameter of the pipe portion thus expanding the pipe portion; c) pulling the punch out of the pipe portion; d) covering the expanded pipe portion with the ring, thus tapering the expanded pipe portion; wherein step d) is performed after step c) or simultaneously with step c); and e) rolling a thread in the form of a trapezoidal thread having a flank angle of less than 10 at least partially on the pipe portion.

7. The method according to claim 6, wherein the punch and the ring are guided with fixed spacing with respect to each other.

8. The method according to claim 6, wherein the outer pipe in the form of a zinc-coated steel pipe is used to carry out the method.

9. The method according to claim 6, wherein the outer pipe having an outer diameter of more than 60 mm and a wall thickness of less than 3 mm is used to carry out the method.

10. The method according to claim 6, wherein the outer pipe having an outer diameter of more than 60 mm and a wall thickness of less than 2.7 mm is used to carry out the method.

11. A method for reinforcing and calibrating of at least a thin-walled pipe portion of an outer pipe of a telescope-like support for the construction sector, comprises the steps of: a) inserting a punch into the pipe portion, the outer diameter of the punch being greater than the inner diameter of the pipe portion thus expanding the pipe portion; b) pulling the punch out of the pipe portion; c) covering the expanded pipe portion with a ring thus tapering the expanded pipe portion, where the inner diameter of the ring corresponds to the outer diameter of the pipe portion before it was expanded; wherein step c) is performed after step b) or simultaneously with step b); and d) rolling a thread in the form of a trapezoidal thread having a flank angle of less than 15 at least partially on the pipe portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 is a perspective cut-out of a telescope-like support according to the invention having an outer pipe and a stop element which is constructed as a cap;

(3) FIG. 2 is a cut-out of a longitudinal section through a telescope-like support which corresponds to FIG. 1;

(4) FIG. 3 is a perspective view of the cap from FIG. 1;

(5) FIG. 4 is a sectioned view of the cap shown in FIG. 3;

(6) FIGS. 5a, 5b and 5c shows the individual portions of the telescope-like support according to the invention before the inner pipe is joined together with the outer pipe; and

(7) FIG. 6a is a sectioned side view of a device for producing the outer pipe in a first position;

(8) FIG. 6b shows the device for producing the outer pipe in a second position;

(9) FIG. 6c shows the device for producing the outer pipe in a third position;

(10) FIG. 6d shows the device for producing the outer pipe in a fourth position;

(11) FIG. 6e shows the outer pipe from FIG. 6d having a thread; and

(12) FIG. 6f is a cut-out from FIG. 6e.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(13) FIG. 1 shows a selected support portion of a telescope-like support according to the invention for the construction sector, which support is generally designated 10. The telescope-like support 10 has an outer pipe 12 according to the invention and an inner pipe 14 which is arranged so as to be able to be axially displaced therein. The inner pipe 14 has at the free end 16 thereof illustrated at the top in the Figure a carrier plate 18 known per se whilst the outer pipe 12 has at the foot-side end not illustrated in greater detail in the Figure a foot plate for secure positioning on a respective substrate.

(14) At an upper end 20 of the outer pipe 12, that is to say, an end facing the carrier plate 18 of the inner pipe 14, there is arranged a cap 22 which acts as a stop element for the inner pipe 14 and by means of which the inner pipe 14 is prevented from being axially removed from or falling out of the outer pipe 12.

(15) The cap 22 is constructed in a manner corresponding to a union nut and has a substantially cylindrical wall portion 24 having an inner thread 26. The cylindrical wall portion 24 is adjoined by an edge region 28 of the cap 22, which region 28 is arranged in the Figure above the cylindrical wall portion 24, is angled with respect to the cylindrical wall portion 24 radially in the direction towards a longitudinal axis 30 of the telescope-like support 10 and partially covers a free cross-section surface-area 32 of the outer pipe 12.

(16) The cap 22 or the inner thread 26 thereof is located in engagement with an outer thread 36 which is arranged on the outer covering face 34 of the outer pipe 12. At the same time, there engages in the outer thread 36 of the outer pipe 12 a so-called recessed nut 38 on which a handle 38 is pivotably arranged and which can be moved axially along the outer pipe 12 by means of rotation about the longitudinal axis 30 of the telescope-like support 10.

(17) There is supported on the recessed nut 38 a securing pin 40 which is inserted transversely relative to the longitudinal axis 30 of the telescope-like support 10 through the outer and inner pipe 12, 14. In this regard, the outer pipe 12 has two mutually opposed, elongate first insertion openings which extend parallel with the longitudinal axis 30 of the telescope-like support 10, whilst the inner pipe 14 has a plurality of circular, mutually opposed (aligned) second insertion openings 44 which are arranged along the inner pipe 14 with regular spacing from each other above or below each other, respectively.

(18) For approximate length adjustment of the telescope-like support 10, the inner pipe 14 is first withdrawn as far as a desired length of the telescope-like support 10 and the securing pin 10 is subsequently inserted through the first insertion openings 42 of the outer pipe and second insertion openings 44 of the inner pipe 14 which are in alignment therewith.

(19) By rotating the recessed nut 38 which is arranged below the securing pin 40 in the Figure, the relative position thereof along the outer pipe 12 can subsequently be adjusted in a stepless manner. At the same time, the axial support position of the securing pin 40 on the outer pipe 12 or the inner pipe 14 which is coupled thereto along the outer pipe 12, that is to say, the length of the telescope-like support 10, can thereby be finely adjusted in accordance with requirements.

(20) As can be seen in particular in FIG. 2, a longitudinal section over a part-region of the telescope-like support 10, the cap 22 covers with the angled edge region thereof an end face 46 of one end 20 of the outer pipe 12. The inner pipe 14 has a stop means 48 which is constructed as an expanded end and which can be brought into abutment with the cap 22 or the angled edge region 28 thereof in order to prevent the inner pipe 14 from falling out of the outer pipe 12 if no other securing elements are effective.

(21) The inner pipe 14 additionally has a plurality of knob-like projections 50 which are arranged with spacing from the stop means (expanded end) 48 of the inner pipe 14 and which protrude laterally in a radial direction over an outer covering face 34 of the inner pipe 14. The knob-like projections 50, when a predetermined maximum withdrawal extent of the inner pipe 14 is reached, are brought into abutment with the cap 22 and thus necessitate a minimum length of the inner pipe 14 remaining in the outer pipe 12. In the event of bending torques occurring, the inner pipe 14 is therefore supported on an inner covering face 52 of the outer pipe 12, whereby the cap 22 can be reliably prevented from being levered off the outer pipe 12.

(22) The knob-like projections 50 have a function similar to the stop means 48 and limit the telescoping length of the telescope-like support.

(23) The inner thread 26 of the cap 22, as shown in greater detail in FIGS. 3 and 4, is constructed as a flat profile and has a thread profile 54 which is interrupted along the thread.

(24) The illustration in FIG. 4 shows that there is arranged on the cylindrical cap portion 24 of the cap 22 a rotation prevention means 56 which is constructed as a hammering flap and which, after the cap has been screwed onto the outer thread 36 (FIGS. 1 and 2) of the outer pipe 12, is hammered into the outer thread 36 of the outer pipe 12 and which securely engages in an opening 57 (see FIG. 5) in the outer thread 36 of the outer pipe 12.

(25) FIGS. 5a, 5b and 5c shows the individual components of the telescope-like support 10 according to the invention before the inner pipe 14 is joined together with the outer pipe 12. In particular FIG. 5a shows the securing pin 40, FIG. 5b shows the outer pipe 12 and FIG. 5c shows the inner pin 14. The support plate 18 explained above is already welded to the inner pipe 14, whilst a foot plate 58 is welded to the foot-side end of the outer pipe 12. The recessed nut 38 is screwed to the outer thread 36 of the outer pipe 12, whilst the cap 22 is pushed onto the inner pipe 14 and prevented from being axially removed from the inner pipe 14 by the knob-like projections 50 or the carrier plate 18. In order to join the inner pipe 14 to the outer pipe 12, the inner pipe 14 is inserted axially into the outer pipe 12 with the expanded end 48 thereof (stop means) at the head-side end 20 of the outer pipe 12 until at least the knob-like projections 50 come to rest inside the outer pipe 12. Subsequently, the cap 22 is screwed onto the outer thread 36 of the outer pipe 12 and the insertion flap 56 is hammered with a tool into the opening 57 of the outer pipe 12.

(26) FIG. 6a is a sectioned side view of a device 60 for carrying out a method according to the invention for producing the outer pipe 12. The device 60 is illustrated in a first position. The device 60 is illustrated in a highly simplified and schematic manner. Guides, drives and the like of the device 60 have not been illustrated for reasons of clarity.

(27) The outer pipe 12 is in an unprocessed state in FIG. 6a. The outer pipe 12 may be a zinc-coated steel pipe having an outer diameter of over 60.3 mm, in particular 71 mm, 76.5 mm, 83 mm or 83.5 mm, and a wall thickness of 2.6 mm. The outer pipe is clamped at the right-hand side in a clamping device (not illustrated) of the device 60.

(28) The outer thread 36 (see FIGS. 1, 2, 5) of the outer pipe 12 could not be rolled in the state of the outer pipe 12 illustrated in FIG. 6a since the ratio of the outer diameter to the wall thickness and the tolerance of the outer diameter of the outer pipe is too great in this regard in the case of the outer diameter and wall thicknesses set out. In the method according to the invention which is illustrated in FIGS. 6a to 6d, the outer pipe 12 is therefore reinforced in the region of the shaping and the outer diameter is calibrated, that is to say, the tolerance of the outer diameter is reduced.

(29) To this end, the device 60 has according to FIG. 6a a punch 62 and a ring 64. The punch 62 and the ring 64 are constructed so as to be rotationally symmetrical with respect to the longitudinal axis of the outer pipe 12 illustrated with dot-dash lines. The inner diameter of the inner covering face 66 of the ring 64 corresponds to the calibrated outer diameter, that is to say, the outer diameter of the outer pipe 12 to be obtained. Furthermore, the inner covering face 66 of the ring 64 is constructed in a circular manner in order to achieve improved roundness of the outer covering face of the outer pipe 12.

(30) The ring 64 has a first rounded portion 68 and a second rounded portion 70 in order to be able to be better guided over the outer pipe 12.

(31) FIG. 6b shows the device 60 in a second position. The punch 62 and the ring 64 are pushed together to the right in this illustration. The punch 62 is connected to the ring 64 in this instance. The connection between the punch 62 and the ring 64 is not illustrated in the illustrations of FIGS. 6a-6d for reasons of clarity. The inner diameter of the ring 64 substantially corresponds to the outer diameter of the unprocessed outer pipe 12. The ring 64 can therefore be pushed onto the outer pipe 12 with little application of force.

(32) FIG. 6c shows the device 60 in a third position. The punch 62 has been partially introduced into the outer pipe 12 under the application of force. In order to make it easier to introduce the punch 62, it has a third rounded portion 72. When the punch 62 has been introduced to a great extent into the outer pipe 12, a fourth rounded portion 74 enables easy extraction from the outer pipe 12 (not shown). Owing to the introduction of the punch 62, the outer pipe 12 is expanded in a first pipe portion 76 by cold shaping. The first pipe portion 76 thereby becomes slightly longer and the wall thickness in the first pipe portion 76 somewhat smaller.

(33) FIG. 6d shows the device 60 in a fourth position. The punch 62 has been moved together with the ring 64 to the left away from the outer pipe 12. In this instance, the ring 64 has been pulled over the expanded first pipe portion 76 with the application of force. The outer diameter of the expanded first pipe portion 76 has thereby again been tapered to the original outer diameter of the pipe 12 according to FIG. 6a. The roundness and tolerance of the outer diameter was improved in this instance. The tapering further brings about a cold shaping of the first pipe portion 76. A further reinforcement of the first pipe portion 76 is thereby achieved. The wall thickness of the first pipe portion 76 was decreased, whereas the length of the outer pipe 12 was increased.

(34) The device 60 in FIG. 6d is in the same position as in FIG. 6a. FIGS. 6a to 6d therefore show a complete cycle of the previously described method. Such a cycle lasts approximately 8 seconds, the punch 62 being introduced approximately 300 mm into the pipe portion 76.

(35) Owing to the processing of the first pipe portion 76, the outer thread 36 can now be readily rolled on the first pipe portion 76.

(36) FIG. 6e shows the outer pipe 12, the first pipe portion 76 having the outer thread 36. The outer thread 36 was rolled on the first pipe portion 76. In FIG. 6e, a cut-out 78 of the outer thread 36 is indicated.

(37) FIG. 6f shows the cut-out 78 of the outer thread 36 from FIG. 6e. From FIG. 6f, it can be seen that the outer thread 36 has a flank angle F. The flank angle F is 10 (for reasons of clarity, a larger angle is shown in the drawing). Owing to the small flank angle of less than 15, fewer inwardly directed radial forces have to be taken up by the outer pipe 12 when the outer thread 36 is subjected to loading.

(38) In summary, the invention relates to a method and a device for producing an outer pipe of a telescope-like support and the telescope-like support and the outer pipe which is contained therein. For reasons of weight and stability, the outer pipe can be produced from a standardized zinc-coated steel pipe having a large outer diameter and a small wall thickness. A pipe portion of the outer pipe is expanded in the method with a punch and subsequently tapered to the original outer diameter again with a ring. A reinforcement of the pipe portion and a calibration of the outer diameter of the pipe portion are thereby achieved. An outer thread can be rolled on the pipe portion.