WO2002027198A1

WO2002027198A1 - Secured screw connection

Info

Publication number: WO2002027198A1
Application number: PCT/DE2001/003703
Authority: WO
Inventors: Arno Giehl
Original assignee: Arno Giehl
Priority date: 2000-09-27
Filing date: 2001-09-27
Publication date: 2002-04-04
Also published as: DE10066076A1; DE10194132D2; DE10194133D2; AU2002213817A1; DE10049092A1; WO2002027199A1

Abstract

The invention relates to a secured screw connection, comprising a threaded shaft (12); a threaded bore (11); at least one locking element (13, 13') which is mounted on the threaded shaft (12) or on the threaded bore (11) and which projects radially outwards; and at least one locking recess (15) for receiving the locking element (13, 13'), said recess being configured on the threaded bore (11) or on the threaded shaft (12). Both variants of this type of the secured screw connection are known from DE 43 40 504 A1. The aim of the invention is to provide secured screw connections of the aforementioned type that can be tightened slightly while still being reliably secured against unintentional loosening. To this end, both variants provide that the locking recesses (15) and/or the locking elements (13, 13') are configured in such a way that the loosening locking force is greater than the tightening locking force.

Description

SECURED SCREW CONNECTION

In a first variant, the present invention relates to a secured screw connection, comprising: a threaded shaft; - a threaded hole; at least one locking element which is attached to the threaded shaft and projects radially outwards; and at least one locking recess for receiving the locking element, which on the

Threaded bore is formed.

In a second variant, the present invention relates to a secured screw connection, comprising: a threaded shaft; a threaded hole; at least one locking element which is attached to the threaded bore and projects radially inwards; and at least one locking recess for receiving the locking element, which is formed on the threaded shaft.

Both such variants of the secured screw connection are known from DE 43 40 504 A1.

A correctly designed screw connection that is reliably preloaded generally does not require additional screw locking. By loosening as a result of setting or creeping of the connecting elements or by automatically loosening as a result of relative movements between the contact surfaces, the required pretensioning force can, however, be undercut in some cases. Creep can be observed, for example, when tensioning low-strength copper sheets or painted steel sheets even at room temperature, while relative movements between the contact surfaces occur, especially with thin tensioned parts and loads perpendicular to the axial direction of the screw with insufficient pre-tensioning force. In the secured screw connections known from DE 4340 504 A1, both the locking element, which is a spring clip there, and each locking recess each lie in a plane in which the longitudinal axis of the screw connection extends. Consequently, the locking elements and the locking recesses are formed symmetrically to the longitudinal axis.

It is therefore an object of the invention to provide secured screw connections of the type mentioned at the beginning, which can be easily tightened and yet are reliably secured against unintentional loosening.

In both variants, this object is achieved in that the latching depressions and / or the latching elements are designed in such a way that the release latching force is greater than the tightening latching force.

The threaded shank can be, for example, the externally threaded shaft of a screw, and the threaded bore can be provided on a workpiece, such as an engine block, or the internally threaded bore of a nut.

If the locking element protrudes into the locking recess when the screw connection is tightened, the screw connection can only be released again by overcoming the release locking force. The latching element and the latching recess can be designed such that the tightening latching force that has to be overcome for further tightening is less than the releasing latching force.

A threaded shaft in the sense of the present invention is also understood to mean a shaft which has an external thread only over part of its length. In this case, the locking element of the first variant or the locking recess of the second variant can also be attached to a section of the threaded shaft that does not have an external thread.

Threaded bore in the sense of the present invention is also understood to mean a bore which has an internal thread only over part of its length. In this case, the locking recess of the first variant or the locking element of the second variant can also be attached to a section of the threaded bore that does not have an internal thread.

In both variants, it can be provided that the secured screw connection has a nut with: an outer body which has an axial through opening; an inner body which is accommodated in the through opening so as to be displaceable in the axial direction, has a threaded bore and is divided in the axial direction into at least two jaws, each of which has a segment of the internal thread on its radially inner surface and is guided in the through opening in this way, that when the outer body is displaced in an axial direction relative to the inner body, they are moved apart and when the outer body is displaced in the opposite axial direction relative to the inner body, they are closed.

Such a shared mother is known, for example, from the published French patent application FR 2 640 336, the published German patent application DE 40 24 784 or the as yet unpublished German patent application DE 100 23 675, reference being made to the content of these three documents. This split nut enables the screw connection to be loosened quickly and easily without having to unscrew it against the release latching force. If the jaws are moved apart, not only is the engagement between the internal thread segments and the external thread of the threaded shaft reduced, but also the engagement between the latching element and the latching recess, which reduces the release latching force. The jaws can be moved so far apart that neither the internal thread segments and the external thread nor the locking element and locking recess are in engagement with one another, so that in this state the nut can be moved axially on the threaded shaft.

In this case, it can be provided in a first alternative that the jaws are displaced radially outward when the outer body is displaced relative to the inner body in the release direction and are displaced radially inward when the outer body is displaced relative to the inner body in the tightening direction. This first alternative is described in the above-mentioned DE 100 23 675.

In a second alternative it can be provided that: the jaws each have a front section which carries the respective internal thread segment and an integral rear section which is shaped like the front section, but is slightly angled outwards relative to this and instead of the Internal thread segment has a non-threaded recess, the internal dimensions of which is larger than the internal thread segment; and the jaws at the transition point between the front sections and the rear sections are pivotally mounted to one another such that the front sections are opened when the outer body is displaced relative to the inner body in the loosening direction of the nut, and when the outer body is displaced relative to the inner body in the tightening direction of the nut will be closed.

This second alternative is described in the above-mentioned DE 40 24 784.

In both variants, it can also be provided that the secured screw connection has a screw with: an outer body, which encompasses the threaded shaft and is divided in the axial direction into at least two legs, each having a shaft section which carries a segment of the external thread, and are biased radially inward; and an inner body which is arranged between the legs so as to be displaceable in the axial direction, the legs being able to be moved radially inward when the inner body is pulled out between the legs in the loosening direction of the screw.

Such a split screw is known, for example, from the as yet unpublished German patent application DE 100 36 194, reference being made to the content of this document. Similar to the split nut described above, this split screw also enables quick and easy loosening of the screw connection without having to unscrew it against the release latching force. If the legs are moved inwards, then not only that Engagement between the external thread segments and the internal thread of the threaded bore is reduced, but also the engagement between the locking element and the locking recess, which reduces the release locking force. The legs can be moved so far inward that neither external thread segments and internal threads nor the locking element and locking recess are in engagement with one another, so that in this state the screw can be moved axially in the threaded bore.

It can further be provided that the latching element is anchored in a side surface of the inner body, which forms a section of the peripheral surface of the threaded shaft that does not have an external thread.

In addition, it can be provided that the locking recess is an axial groove.

Furthermore, it can be provided that the latching depressions and / or the latching elements are designed asymmetrically to the longitudinal axis of the screw connection in such a way that the release latching force is greater than the tightening latching force.

In addition, it can be provided that each latching recess has an oblique right flank that moves radially inward from the left, radially extending flank.

In addition, it can be provided that each locking element is inclined to the left when it is in a locking recess.

Further features and designs of the invention are described in the subclaims.

Preferred exemplary embodiments are described in more detail below with reference to the accompanying drawings:

FIG. 1 is a cross section of a secured screw connection in a first embodiment according to the first variant; FIG. 2 is a cross section of a secured screw connection in a second embodiment according to the first variant;

FIG. 3 is a cross section of a secured screw connection in a third embodiment according to the first variant;

FIG. 4 is a cross section of a secured screw connection in a fourth embodiment according to the second variant;

FIG. 5 is a sectional side view of a secured screw connection in a fifth embodiment according to the first variant with a split nut with the jaws open;

FIG. 6 is a cross section along the line VI-VI of FIG. 6;

FIG. 7 shows the screw connection of FIG. 5 with the jaws closed;

FIG. 8 is a cross section along the line VIII-VIII from FIG. 7;

FIG. 9 is a side view of a jaw for the nut of FIG. 5 to 8;

FIG. 10 is a sectional side view of a secured screw connection in a sixth embodiment according to the second variant with a split screw in which the legs are closed;

FIG. 11 is a cross section along the line Xl-Xl from FIG. 10;

FIG. 12 shows the screw connection of FIG. 10 with the legs spread apart;

FIG. 13 is a cross section taken along the line Xlll-Xlll from FIG. 12;

FIG. 14 is a top view of the inner body of the screw of FIG. 10 to 13;

FIG. 15 is a side view of the inner body of FIG. 14; FIG. 16 is a cross section of a secured screw connection in a seventh embodiment according to the first variant with a split screw in which the legs are spread apart; and

FIG. 17 is a top view of the inner body of the screw of FIG. 16th

In FIG. 1 shows a secured screw connection in a first embodiment. It has a nut 10 with a threaded bore 11 and a threaded shaft 12. In the lower half of FIG. 1, the nut 10 and the threaded shaft 12 are shown separately.

A locking element 13 is attached to the threaded shaft 12 and projects radially outwards. The locking element 13 here consists of a spring plate which is anchored with an edge in the threaded shaft 12 and whose opposite free edge runs parallel to the longitudinal axis A of the screw connection. Four locking recesses 15 are formed on the threaded bore 11 and are arranged at the same angular distance of 90 ° around the longitudinal axis A. Each locking recess 15 is an axial groove here, which extends over the length of the threaded bore 11.

According to FIG. 1 is the free edge of the locking element 13 in the upper locking recess 15, so that the screw connection is secured against unintentional loosening. This is because the threaded shaft 12 has to rotate to the left relative to the nut 10 from the position shown in order to release it, so that the latching element 13 initially comes into contact with the left flank of the upper latching recess 15 and thereby hinders a further left turn. This is only possible if the torque is so large that the locking element is bent from the adjacent left flank to the right and its free edge slips out of the locking recess. The force required for this torque is also referred to here as release detent force.

If, on the other hand, the screw connection is to be tightened further, then the threaded shaft 12 must rotate from the position shown relative to the nut 10 to the right, so that the latching element 13 initially comes into contact with the right flank of the upper latching recess 15 and thereby a further right turn - hung hampered. As before, this is only possible if the torque is so large that the locking element 13 is bent to the left by the adjacent right flank and slips out of the locking recess 15 with its free edge. The force required for this torque is also referred to here as the locking detent force. Now the threaded shaft 12 can be turned further to the right with less torque, since the bent locking element 13 can be pulled relatively easily over the internal thread until after 90 ° the right locking recess is reached, into which the locking element 13 can snap again.

So that the bent locking element 13 cannot get stuck between the internal thread and the external thread, the external thread has a recess 17 in which the locking element 13 sits and which offers it sufficient space for evasion.

In this first embodiment, the release latching force is equal to the tightening latching force, since the latching element 13 and the latching depressions 15 are symmetrical to the longitudinal axis A. In the FIG. 2 and 3, on the other hand, two modifications of the first embodiment are shown, in which the release latching force is greater than the tightening latching force, so that the screw connection can be loosened more difficult and / or tightened more easily.

In FIG. 2 shows a secured screw connection in a second embodiment. In the right half of FIG. 2, the nut 10 is shown alone.

In contrast to the first embodiment, the locking recesses 15 are not symmetrical here, but each have an oblique right flank, which moves radially inward from the left, radially extending flank. If the threaded shaft 12 is now turned to the right to tighten the screw connection, the latching element 13 initially comes into contact with the right flank only with its free edge, so that it can be bent more easily to the left and as on a wedge surface slips out of the locking recess 15. As a result, the pull-in latching force is smaller than in the first embodiment. In FIG. 3 shows a secured screw connection in a third embodiment. In the right half of FIG. 3, the threaded shaft 12 is shown alone.

In contrast to the first embodiment, the locking element 13 is not symmetrical here, but is inclined to the left when it is located in a locking recess 15. If the threaded shaft 12 rotates to the left to loosen the screw connection from the position shown, then the latching element 13 initially comes into contact only with its free edge in contact with the left flank, so that it is more difficult to bend to the right, since it has only just been set up must be and only then can be bent further. As a result, the release latch force is larger than in the first embodiment.

The second embodiment can of course also be combined with the third embodiment.

In FIG. 4 shows a secured screw connection in a fourth embodiment. In the lower half of FIG. 4, the nut 10 and the threaded shaft 12 are shown separately.

In contrast to the three previous embodiments, the locking element 13 is not attached to the threaded shaft 12 but to the threaded bore 11 and projects radially inwards. Accordingly, the locking recesses 15 are not formed on the threaded bore 11, but on the threaded shaft 12. However, the mode of operation is the same in all embodiments.

In the FIG. 5 to 8, a secured screw connection is shown in a fifth embodiment. This fifth embodiment corresponds to the first embodiment, but has a split nut 10, as described in DE 100 23 675.

The nut 10 has an outer body 16 and two jaws 18, 20. The outer body 16 has an axial through opening 22, in which the jaws 18, 20 are received so as to be displaceable in the axial direction, as will be explained in more detail below. The through opening 22 here has a rectangular cross section and runs coaxially to the longitudinal axis A of the nut 10. The jaws 18, 20 here are rectangular blocks, the length of which corresponds to the length of the outer body 16 and the width of which is slightly smaller than the width of the through opening 22, as shown in FIG. 6 is clearly visible, so that they sit in the through opening 22 in a rotationally fixed manner. Each jaw 18, 20 has on its radially inner surface, that is to say on the surface which faces the threaded shaft 12, an internally threaded segment 24 which is designed to match the external thread of the threaded shaft 12. Thus, the one shown in FIG. 5 and 6, upper jaw 18 has its internally threaded segment 24 on its underside, while lower jaw 20 carries its internally threaded segment 24 on its upper side.

As shown in FIG. 6 can be clearly seen, the two jaws 18, 20 are distributed symmetrically around the longitudinal axis A and thus also around the threaded shaft 12, that is to say they are at an angular distance of 180 ° to one another. This arrangement also applies accordingly to other embodiments of the nut 10 (not shown) in which more than two jaws are provided: in the case of three jaws, these are then preferably arranged at an angular distance of 120 ° from one another around the longitudinal axis A.

According to FIG. 6, first guide means are provided on the outer body 16, which here comprise four lugs 26 which protrude from the through opening 22. There are two lugs 26 on the in FIG. 6 left and on the right side of the through opening 22 at an equal distance above and below the longitudinal axis A. The lugs 26 are formed here by the inner end of pins which have been inserted from the outside into through holes 28 in the outer body 16.

Suitable for these first guide means on the outer body 16 are shown in FIG. 5, 6 and 9, second guide means are provided on the jaws 18, 20, which here comprise four grooves 30, in each of which one of the lugs 26 runs. Each jaw 18, 20 has on its in the FIG. 6 left side surface a groove 30 and in its right side surface another groove 30 symmetrical to this. Each groove 30 is removed according to FIG. 5 and 9 in the tightening direction from the longitudinal axis A, so that their distance from the longitudinal axis A in FIG. 5 is larger on the left than on the right. Each groove 30 thus extends essentially axially in a plane which is parallel and at a distance from the longitudinal axis A. Although the grooves are straight here, they can also be curved in the axial direction.

In contrast to the first embodiment, the split nut 10 has only two locking recesses 15 (indicated by a dotted line in FIGS. 5 and 7), which are formed on the internally threaded segments 24 of the upper jaw 18 and the lower jaw 20 and with the same angular distance 180 ° around the longitudinal axis A are arranged. The threaded shaft 12 corresponds to that of the first to fourth embodiments, but according to FIGS. 6 and 8, a second locking element 13 ', which is offset by 90 ° to the first locking element 13 about the longitudinal axis A. As in the first to fourth embodiments, this results in the screw connection being in a locked, secured state again after a rotation of 90 °, since either the first locking element 13 or the second locking element 13 ′ is seated in one of the two locking recesses 15.

To simplify the drawings, FIG. 5 to 8 the locking elements 13,

13 'shown only schematically.

In the following with reference to FIG. 5 to 8 described the operation of the split nut 10. In the FIG. 5 and 6, the nut 10 is shown in the open state, in which the jaws 18, 20 are so far apart that their internal thread segments 24 are not in engagement with the external thread of the threaded shaft 12 and also none of the locking elements 13, 13 ' is in engagement with the locking recesses 15. The nut 10 can therefore in this open state to the right in FIG. 5, that is to say in the release direction, are quickly removed from the threaded shaft 12 without having to be rotated about its longitudinal axis A, as is the case with a conventional one-piece nut. This property is particularly advantageous when the release latching force is high. The nut 10 can of course also be quickly pushed onto the threaded shaft 12 to the left, that is to say in the tightening direction, without having to be rotated.

As shown in FIG. 5 can be clearly seen, the outer body 16 is relative to the jaws 18, 20 in the release direction up to the stop of the lugs 26 at the right end of the grooves

30 shifted so that the jaws 18, 20 are only about halfway through Insert the passage opening 22. Since each groove 30 lies with its right end closer to the longitudinal axis A than with its rest, the jaws 18, 20 are so far apart that their internal thread segments 24 are not in engagement with the threaded shaft 12 and neither is the first locking element 13 is in engagement with the upper locking recess 15.

Since the height of the jaws 18, 20 is selected so that with its radially outer surface 32, which is the upper surface of the upper jaw 18 and the lower surface of the lower jaw 20, in this opened state of the nut 10 on the upper or The bottom surface of the through opening 22 is prevented from tipping down over the lugs 30 and then the left lower edge of the upper jaw 18 and the right upper edge of the lower jaw 20 from resting against the threaded shaft 12.

To close the nut 10, this is from the in FIG. 5 position shown so far to the left until the jaws 18, 20 abut with their left end faces on the objects 14 to be connected. If the outer body 16 is pushed further to the left relative to the threaded shaft 12, it is now also displaced to the left relative to the jaws 18, 20 and thus, since these can no longer deflect to the left, pushed onto them. Since the outer body 16 is now displaced relative to the jaws 18, 20 in the tightening direction, the lugs 26 in the grooves 30 likewise run in the tightening direction, so that the jaws 18, 20 are displaced radially inward and are thus closed. Since the jaws 18, 20 are moved radially inward, that is to say towards the threaded shaft 12, their internal thread segments 24 come evenly into engagement with the external thread of the threaded shaft 12 over their entire length. As a result, the internal thread segments 24 become caught and jammed by the external thread an inclined seat of the jaws 18,

20 prevented on the threaded shaft 12. Otherwise there would be a risk that the nut 10 could not be closed completely or, if this should be achieved with excessive force, the threads of the threaded shaft 12 and / or the jaws 18, 20 would be damaged.

When the outer body 16 is pushed completely onto the jaws 18, 20, the nut 10 is in the closed state, which is shown in FIGS. 7 and 8 is shown. In FIG. 7 it can be clearly seen that the lugs 26 in the left end de of the grooves 30 sit so that the internal thread segments 24 together form part of an internal thread that fits the external thread of the threaded shaft 12, as shown in FIG. 8 is clearly visible. The jaws 18, 20 thus together form an inner body which is accommodated in the through opening 22 in a rotationally fixed manner and displaceably in the axial direction and has an axial internal thread, as is required by a nut 10. Conversely, it can be said that the inner body is divided into two jaws 18, 20 in the axial direction.

If the nut 10 in the in the FIG. 7 and 8 is shown closed state, then it can be tightened like a conventional one-piece nut, since the inner body 18, 20 sits in the through opening 22 in a rotationally fixed manner.

In this closed state, the first latching element 13 is also seated in the upper latching recess 15, so that the screw connection is secured.

This fifth embodiment can of course also be varied so that, similarly to the fourth embodiment, the two locking elements 13 are attached to the internal thread segments 24 and the two locking recesses 15 are formed on the threaded shaft 12 for this purpose. In order to ensure a snap-in here after each rotation by 90 °, the snap-in elements 13 are then at an angular distance of 180 ° and the snap-in depressions 15 are at an angular distance of 90 ° to one another.

In the FIG. 10 to 13 is a secured screw connection in a sixth

Embodiment shown. This sixth embodiment corresponds to the fourth embodiment, but has a split screw 110, as described in DE 100 36 194.

The screw 110 has an inner body 113 and an outer body which is divided into two legs 114, 115 in the axial direction. Each leg 114, 115 has a shaft section 116, which carries a segment of the external thread of the screw 110, and a head section 117, which with the in the FIG. 10 and 12 left end of the shaft portion 116 is connected. In contrast to the fourth embodiment, the divided screw 12 has only two latching depressions 15 (indicated by a dotted line in FIGS. 10 and 12), which are formed on the external thread segments of the upper leg 114 and of the lower leg 115 and are of the same angle. stood at 180 ° around the longitudinal axis A. The nut 10 corresponds here to that of the first to fourth embodiments, but according to FIG. 11 and 13 have a second locking element 13 ', which is offset by 90 ° to the first locking element 13 about the longitudinal axis A. As in the first to fourth embodiments, this results in the screw connection being in a locked, secured state again after a rotation of 90 °, since either the first locking element 13 or the second locking element 13 ′ is seated in one of the two locking recesses 15.

To simplify the drawings, FIG. 10 to 13, the locking elements 13, 13 'are only shown schematically.

The legs 114, 115 are radially inward, that is, in the in the FIG. 10 and 11 biased closed position shown. For this purpose it is provided here, for example, that the shaft sections 116 have an annular groove 118 in which a snap ring 119 is seated. Additional ring grooves with a snap ring can be provided as required. In addition, deviating from its position at the free end of the shaft sections 116, the annular groove 118 can also be provided at another location on the shaft sections 116.

According to FIG. 10 and 12, a first bore 120 is formed in the head section 117 of the upper leg 114 and runs from top to bottom at right angles to the longitudinal axis A of the screw 110. A corresponding second bore 121 is in the head section 117 of the lower leg 115 in alignment with the first

Bore 120 formed. A guide pin 122 is seated with its upper end in the first bore 120 and with its lower end in the second bore 121, so that the two legs 114, 115 can be displaced radially but not axially relative to one another. The two bores 120, 121 are designed here as through bores and each have a diameter in the radially outer section that is larger than the diameter of the guide pin 122. The two head ends of the guide pin 122 lie in these radially outer sections, which have a larger diameter than the rest of the guide pin 122. Thus, the guide pin 122 cannot slip out of the bores 120, 121. The assembly of the guide pin 122 is described below.

Each head section 117 has a radially inner surface 123 which, starting from the left end face of the head section 117, initially runs parallel to the longitudinal axis A and then diagonally radially inwards to the longitudinal axis A.

The inner body 113 essentially has the shape of a rod with a rectangular cross section. Its tip end (right in FIGS. 10 and 12) is wedge-shaped to match the radially inner surfaces 123. In the in the FIG. In the closed state shown in FIG. 10, the upper and lower wedge surfaces 124 of the tip end of the inner body 113 bear against the inclined section of the radially inner surface 123 of the upper and lower head sections 117, respectively. The middle part 125 of the inner body 113 adjoining the tip end has a height which corresponds to the distance between the parallel sections of the radially inner surfaces 123 of the two head sections 117 in the position shown in FIG. 12 corresponds to the closed state shown. Therefore, these parallel sections rest on the top or bottom of the central part 125. The length of the middle part 125 corresponds to the length of the shaft sections 116. The head end 126 of the inner body 113 adjoining the middle part 125 has an upper side and a lower side which are designed to match the radially inner surfaces 123 of the two head sections 117. Therefore, the head end 126 lies in the spread state with its top and bottom on the radially inner surfaces 123, and in this spread state the middle part 125 lies with its top and bottom on the bottom of the upper shaft portion 116 and on the top of the lower sheep - Section 116.

In the FIG. 14 and 15, the inner body 113 is shown in top and side views. It has an axial slot 127, which extends over the entire length of the central part 125 into the head end 126 and opens into the top and the bottom of the inner body 113. The guide pin 122 is shown in FIG. 10 and 12 passed through the slot 127, so that the inner body 113 is captively connected to the legs 114, 115. As shown in FIG. 11, the shaft sections 116 have a cross-sectional area in the form of a circular segment, the radius of which corresponds to the radius of the external thread of the screw 110 and the radius of the internal thread 111 of the nut 10, and the central angle of which is less than 180 °. This central angle is chosen so that in the closed state with coaxial alignment of the nut

10 and screw 110, no shaft section 116 with its external thread segment is in engagement with the internal thread 111, that is to say that the width of the shaft section 116 is smaller than the internal diameter of the internal thread 111 and the height of the shaft section 116 is smaller than the internal radius of the internal thread 111.

In the following with reference to FIG. 10 to 13 describe the operation of the split screw 110. In the FIG. 10 and 11, the screw 110 is shown in the closed state, in which the legs 114, 115 are so close to one another that their external thread segments are not in engagement with the internal thread 111 of the nut 10 and also none of the latching elements 13, 13 'are in engagement the recesses 15 is. The screw 110 can therefore in this closed state to the right in FIG. 10, ie in the tightening direction, can be quickly pushed into the nut 10 without having to be rotated about its longitudinal axis A, as is the case with a conventional one-piece screw. This property is particularly advantageous when the release latching force is high.

The screw 110 can of course also be quickly pulled out of the nut 10 to the left, that is to say in the release direction, without having to be rotated.

As shown in FIG. 10 can be clearly seen, the inner body 113 is displaced relative to the legs 114, 115 in the release direction up to the stop of the guide pin 122 at the right end of the slot 127, so that its tip end is located between the head sections 117. Since the legs 114, 115 are prestressed radially inward with the aid of the snap ring 119, their radially inner surfaces, that is to say the underside of the upper leg 114, and the top of the lower leg 115 lie against one another.

For spreading the screw 110, the inner body 113 from the in FIG. 10 shown position relative to the legs 114, 115 pushed to the right, which due to the wedge action between the wedge surfaces 124 at the tip end of the inner body pers 113 and the inclined sections of the radially inner surfaces 123 of the head section 117 are first pressed radially outward in the region of the head section 117 and come into engagement with the internal thread 111 with the regions of the shaft sections 116 adjoining the head section 117. When the inner body 113 is pushed so far to the right that its tip end between the

Shaft sections 116 lies, then the legs 114, 115 are not further spread in the area mentioned, but are held in the spread position reached. The inner body 113 is pushed further to the right between the legs 114, 115, which are now pressed radially outward in the regions of the shaft sections 116 lying further to the right and come into engagement with the internal thread 111. If the head end 126 lies between the head sections 117 and rests with its oblique sections against the oblique sections thereof, then the inner body 113 is pushed completely between the legs 114, 115, so that the screw 110 is in the spread state, which is shown in FIGS , 12 and 13 is shown. In FIG. 12 can be clearly seen that the guide pin

122 sits at the left end of slot 127.

In FIG. 13, it can be clearly seen that the external thread segments of the shaft sections 116 together form the external thread of the screw 110, which fits the internal thread 111 of the nut 10. The legs 114, 115 thus together form an outer body which carries an external thread, as is required by a screw 110. Conversely, it can be said that the outer body is divided into two legs 114, 115 in the axial direction. The shaft sections 116 of the legs 114, 115 together with the middle part 125 of the inner body 113 form the threaded shaft 12 of the screw 110, the outside diameter of which matches the outside diameter of the inside thread 111 of the nut 10 and the sum of the heights of the two shaft sections 116 and Height of the middle part corresponds to 125.

If the screw 110 is in the position shown in FIG. 12 and 13 is shown in the spread state, it can then be tightened like a conventional one-piece screw. This is done with a conventional tool, such as a screwdriver or wrench, which engages the head of the screw 110, which in this spread state is removed from the head sections 117 of the legs 114, 115 and the head end 126 of the inner body 113 is formed.

In this spread state, the first latching element 13 is also seated in the upper latching recess 15, so that the screw connection is secured.

This sixth embodiment can of course also be varied such that, similarly to the first embodiment, the two latching elements 13 are attached to the legs 114, 115 and the two latching depressions 15 are formed on the threaded bore 11 for this purpose. In order to ensure a snap-in here after each rotation by 90 °, the snap-in elements 13 are then at an angular distance of 180 ° and the snap-in depressions 15 are at an angular distance of 90 ° to one another.

For assembly, the guide pin 122, which is initially only on its in the FIG. 12 has an upper end a head end, in the spread state of the screw 110 with its lower end inserted into the second bore 121 and pushed through the slot 127 so far from below into the first bore 120 that its head end on the shoulder of the second bore 121 supports where its diameter decreases. Then the head end is pushed up and the upper end of the guide pin 122 is compressed so that, like the lower end, it becomes a head end which is supported on the shoulder of the first bore 120, where its diameter decreases.

In the spread state of the screw 110, the guide pin 122 is supported with its head ends on the shoulders of the two bores 120, 121 and is therefore under tension. As a result, the two limbs 114, 115 are pressed radially inward against the inner body 113, so that it is difficult to pull out the inner body 113.

In FIG. 16 shows a secured screw connection in a seventh embodiment. This seventh embodiment corresponds to the first embodiment, but like the sixth embodiment has a split screw 110 as described in DE 100 36 194. In contrast to the sixth embodiment, only one locking element 13 is provided here, which is shown in FIG. 16 left side surface of the central part 125 of the inner body 113 is anchored. In FIG. 17, this inner body 113 of the split screw 10 is shown in a top view. Since, as already mentioned above, the central part 125 together with the shaft sections 116 of the legs 114, 115 form the threaded shaft 12 of the screw 110, the latching element 13, as in the first embodiment, is attached to the threaded shaft 12 However, here lies in a section of the threaded shaft 12 which does not have an external thread.

Since the locking recess 15 is an axial groove that extends over the length of the threaded bore 11, the inner body 113 can be pulled out in the axial direction between the two legs 114, 115 without the threaded shaft 12 having to be rotated in the threaded bore 11 ,

LIST OF REFERENCE NUMBERS

longitudinal axis

mother

threaded hole

threaded shaft

Objects to be screwed into place

latching depression

outer body

Upper jaw recess lower jaw

Through opening

Internal thread segment

nose

Through holes

Grooves radially outer surfaces of the jaws 18, 20 inner wedge surfaces

screw

Inner body upper leg lower leg

shank portion

header

ring groove

Snap ring first hole second hole

Guide pin radially inner surface of the head portion 117

Wedge surface at the tip end of the inner body 113

Middle part of the inner body 113 126 head end of inner body 113

127 slot

Claims

PATENT CLAIMS

1. Secured screw connection, with: a threaded shaft (12); a threaded bore (11); - At least one locking element (13, 13 ') which is attached to the threaded shaft (12) and projects radially outwards; and at least one locking recess (15) for receiving the locking element (13, 13 '), which is formed on the threaded bore (11), characterized in that the locking recesses (15) and / or the locking elements (13, 13') are designed such that the release locking force is greater than the pull-on locking force.

2. Secured screw connection, with: a threaded shaft (12); a threaded bore (11); - At least one locking element (13, 13 ') which is attached to the threaded bore (11) and projects radially inwards; and at least one locking recess (15) for receiving the locking element (13, 13 '), which is formed on the threaded shaft (12). characterized in that the latching depressions (15) and / or the latching elements (13, 13 ') are designed in such a way that the release latching force is greater than the tightening latching force.

3. Secured screw connection according to claim 1 or 2, characterized in that it has a nut (10) with: an outer body (16) which has an axial through opening (22); - An inner body (18, 20) which is slidably received in the through opening (22) in the axial direction, the threaded bore (11) and is divided in the axial direction into at least two jaws (18, 20), each of which is radial inner surface carry a segment of the internal thread and are guided in the through opening (22) such that when the outer body (16) is displaced relative to the inner body (18, 20) in an axial direction, they are moved apart and when the outer body ( 16) is displaced relative to the inner body (18, 20) in the opposite axial direction, can be closed.

4. Secured screw connection according to claim 3, characterized in that the jaws (18, 20) when the outer body (16) is displaced relative to the inner body (18, 20) in the loosening direction of the nut (10) are displaced radially outwards and, if the outer body (16) is displaced relative to the inner body (18, 20) in the tightening direction of the nut (10), be displaced radially inwards.

5. Secured screw connection according to claim 3, characterized in that: - the jaws (18, 20) each have a front section which carries the respective internal thread segment, and an integrally connected rear section which is shaped similarly to the front section, but relative to this is angled slightly outwards and instead of the internal thread segment has a non-threaded recess, the internal dimensions of which is larger than the internal thread segment; and the jaws (18, 20) at the transition point between the front sections and the rear sections are pivotally mounted to one another such that the front sections when the outer body (16) is displaced relative to the inner body (18, 20) in the loosening direction of the nut (10) , are opened and, when the outer body (18, 20) is moved relative to the inner body (16) in the tightening direction of the nut (10), are closed.

6. Secured screw connection according to one of the preceding claims, characterized in that it has a screw (110) with: an outer body (114, 115) which comprises the threaded shaft (12) and in the axial direction in at least two legs (114, 115) which each have a shaft section (116) which carries a segment of the external thread and are biased radially inwards; and an inner body (113) which is arranged between the legs (114, 115) so as to be displaceable in the axial direction, the legs (114, 115) when the inner body (113) in the loosening direction of the screw (110) between the

Legs (114, 115) is pulled out, can be moved radially inward.

7. Secured screw connection according to claim 6, characterized in that the latching element (13) is anchored in a side surface of the inner body (113) which forms a portion of the peripheral surface of the threaded shaft (12) which does not carry an external thread.

8. Secured screw connection according to one of the preceding claims, characterized in that the latching recess (15) is an axial groove.

9. Secured screw connection according to one of the preceding claims, characterized in that the latching recesses (15) and / or the latching elements (13, 13 ') are designed asymmetrically to the longitudinal axis (A) of the screw connection that the release latching force is greater than that Pull-in force is.

10. Secure screw connection according to one of the preceding claims, characterized in that each latching recess (13, 13 ') has an oblique right flank, which moves radially inward from the left, radially extending flank.

11. Secured screw connection according to one of the preceding claims, characterized in that each locking element (13, 13 ') is inclined to the left when it is in a locking recess (15).