HK1097893B - Fastening element to be anchored in a short blind hole that is not undercut, arrangement comprising such a fastening element, method and placement tool for anchoring such a fastening element - Google Patents

Description

Fastening element for anchoring in a short and non-undercut blind hole, device having such a fastening element, method and installation tool for anchoring such a fastening element

The invention relates to a fastening element for anchoring in a short and non-undercut blind hole according to the preamble of claim 1, to a device having such a fastening element according to the preamble of claim 15, to a method and to a setting tool for anchoring such a fastening element according to the preambles of claims 20 or 24. The fastening element is designed in particular to provide a solution for fastening on a plate-shaped component, for example made of structural steel, in order to be able to fix another component thereto. At the same time the plate-like member should not be drilled through, so that the available anchoring depth is only relatively short, especially if the diameter of the blind hole is substantially equal to the thickness of the member. The short is compared to the diameter of the blind hole.

EP 440896B 1 discloses a fastening element for anchoring in an undercut hole of a plate-like member, such as a front panel of a house. Known fastening elements have a shank portion with a bearing cone at a shank end, which expands in the direction away from the shank. On the shank there is a ring, seen in side view as a bellows-like bend, which is pushed onto the support cone for anchoring and thus spreading apart. The expanded ring surrounds the undercut portion of the hole. The known fastening elements, which can be anchored in a plate, however, can be relatively thin in relation to the hole diameter, which has the disadvantage that: an undercut portion is required for anchoring. The machining of the undercut portion entails additional costs.

The object of the invention is therefore to propose a fastening element which can be fastened in a blind hole without undercut. A blind hole of a relatively short diameter should be available for fastening.

This object is achieved according to the invention by the features of claims 1 and 7. The fastening element according to the invention has a tubular, grooveless pressing sleeve which is located on the shank and can be slid on the shank. For anchoring in the blind hole, a fastening element with a support cone is inserted into the blind hole beforehand and the compression sleeve is pushed onto the support cone. During displacement, the support cone expands the compression sleeve in its end facing the support cone. The flared end is pressed into the wall of the blind hole and thus anchors the fastening element in the blind hole. A force-fitting and form-fitting connection is produced between the expansion of the front end of the clamping sleeve and the blind hole, so that a high anchoring force is achieved even if the blind hole is short. A further advantage of the fastening element according to the invention is that the lateral forces are overcome by the support of the shank of the fastening element by the clamping sleeve in the blind hole. Furthermore, a pressing sleeve which is flush-embedded in the blind hole indicates correct anchoring of the fastening element if the blind hole has a defined nominal depth. The fastening element according to the invention is used in particular for anchoring in structural steel, aluminium or the like, but is also suitable for anchoring in other materials, for example cement. In order to make it easier for the pressure sleeve to be pushed onto the support cone and the resulting expansion of the pressure sleeve, the support cone can be provided with a lubricant.

The hollow conical expansion opening in the form of an angle or an inner support cone on the inner side of the end face of the pressure sleeve facing the support cone also serves to make the pressure sleeve more easily expandable at its end facing the support cone. The material thickness of the compression sleeve is thus reduced at the expanded end of the compression sleeve when the compression sleeve is pushed onto the support cone, so that the compression sleeve can be expanded with a low force.

The hollow conical expansion of the pressure sleeve preferably has a smaller cone angle than the support cone. The pressure sleeve is therefore initially brought into contact with the support cone with its front end facing the support cone when it is pushed onto the support cone. The compression sleeve is first expanded at its front end and pressed into the hole wall. Only with increasing displacement onto the expansion support cone does the pressure sleeve continue to expand from the front end facing the support cone to approximately the middle of the axially shorter pressure sleeve. The expansion of the compression sleeve on the front end has the following advantages: the expansion force is low because the expansion of the compression sleeve takes place only over a short portion of its axial length, and the force with which the compression sleeve is pressed into the bore wall is high because the compression sleeve is pressed into the bore wall only at the front end and therefore with a comparatively small annular surface. As an advantage, a stable anchoring is achieved at low expansion forces. The thin-walled compression sleeve supports this effect.

In order to achieve high anchoring values, a cone angle of the support cone in the range from about 14 ° to 20 °, preferably about 17 °, has proven to be advantageous.

One embodiment of the invention provides that the outer side of the clamping sleeve is roughened at least at the end of the clamping sleeve facing the support cone. The roughening may be, for example, a cross-knurl, and is not suitable for a straight-line roughening if it is axially parallel. When the clamping sleeve is expanded, the roughening is pressed into the wall of the blind hole and thus increases the anchoring force. In addition, if the roughened portion is made by deformation processing such as knurling, for example, the roughening also hardens the surface of the compression sleeve. Thus, if the clamping sleeve and the component with the blind hole are made of the same initial hardness material, the roughened part is pressed into the hole wall itself.

In a preferred embodiment of the invention, the compression sleeve is made of a harder steel, for example, it is made of an alloyed stainless steel (e.g., a4 steel). It is also advantageous for the steel to have a locally increased hardness in the outer end of the compression sleeve facing the bearing cone, which end is pressed into the bore wall when the compression sleeve is expanded. The high hardness is in particular the hardness of the compression sleeve, which is higher than the hardness of the structural steel, in order to enable the fastening element to be anchored in the structural steel with a high anchoring force.

In a development of the fastening element according to the invention, the support cone has a larger diameter at the transition to the shank than the shank, and the support cone transitions with an annular step to the smaller diameter of the shank. That is to say the support cone has a frustoconical shape. If the support cone has the same diameter on its base surface facing away from the shank, which has a larger diameter, and the cone angle of the support cone is the same, the support cone is axially shorter. The pressure sleeve can also be designed to be shorter in the axial direction in relation to the support cone. The fastening element can thus be anchored in a blind hole which is still axially shorter, wherein the anchoring force remains almost constant for otherwise identical proportions. The fastening element according to the invention can thus be anchored in a thinner workpiece plate without having to drill through the workpiece plate or undercut blind holes.

In order to be able to anchor the fastening element with a short anchoring depth and nevertheless a high anchoring force, a construction variant of the invention uses an axially short compression sleeve, the compression point of which extends over a portion which exceeds half of its axial length. The axial length of the pressing region corresponds to the axial length of the bearing cone in the pressing sleeve and/or the axial length of the groove, if the pressing sleeve is provided with a groove. Axial shortening is to be understood as a proportional relationship to the characteristic diameter of the fastening element. The characteristic diameter of the fastening element is the shank diameter thereof or the outer diameter of the undeformed press sleeve. The axial length of the compression sleeve corresponds in one embodiment of the invention to approximately its outer diameter, in another embodiment of the invention even to approximately 2/3% of the outer diameter.

One construction of the invention employs a thin-walled compression sleeve. The thin wall can likewise be regarded as a proportional relationship with the characteristic diameter of the fastening element. The compression sleeve wall thickness is, for example, approximately 1/4 to 1/6 of the shank diameter of the fastening element. A thin-walled compression sleeve can be deformed with a low force, i.e. the force required for expanding the compression sleeve is low, while the force required for pressing the compression sleeve into the bore wall is high for a given expansion force.

If the support cone is supported with its end of greater diameter facing away from the shank on the base of the blind hole, the pressing sleeve may be supported on the base of the blind hole when it is pushed onto the support cone. This is the case in particular when the diameter of the blind bore is relatively large, in which case a large annular gap exists between the larger-diameter end of the support cone and the bore wall. The bottom of the blind hole prevents the pressing sleeve from being pushed onto the support cone and thus prevents the pressing sleeve from expanding. As a result, the anchoring of the fastening element in the blind hole may be impaired. In this way, a construction variant of the invention provides that the shank has an axial extension on the larger-diameter side of the support cone facing away from the shank. The support cone of the fastening element according to the invention is therefore not supported with its larger diameter end on the base of the blind hole, but rather with the axial extension on the base of the blind hole. The support cone is thus axially spaced from the bottom of the blind hole, wherein a short distance of the support cone from the bottom of the blind hole, i.e. an axially short extension, is sufficient. The axial extension is short in order not to unnecessarily lengthen the necessary anchoring depth and thus the depth of the blind hole. An axial distance is obtained between the blind hole and the clamping sleeve by the axial projection, so that the bottom of the blind hole does not prevent the clamping sleeve from being axially displaced and expanded. The advantage of this embodiment of the invention is that the anchorage of the fastening element in the blind hole is improved, since the bottom of the blind hole does not prevent the pressing sleeve from being pushed onto the bearing cone and thus does not prevent the fastening element from being anchored in the blind hole.

In order not to prevent the pressure sleeve from being pushed onto the support cone, the projections may not project laterally beyond the support cone. In particular, the diameter of the extension is not greater than the large diameter end of the support cone. A cylindrical axial extension having the same diameter as the larger diameter of the support cone seems suitable. The extension may also taper outwardly from the support cone or be of smaller diameter than the support cone. The axial extensions need not have a circular cross-section.

The holding-down sleeve of the slot makes the spreading easier or increases the spreading force with which the holding-down sleeve is pressed into the hole wall. Compared with a grooved compression sleeve, the non-grooved compression sleeve has the disadvantage of larger expansion force, but has the following advantages: the contact on the hole wall is large and said contact is continuous in the circumferential direction and not interrupted by undercuts. Both a slotted and an unslotted compression sleeve are therefore considered to be in accordance with the invention.

In one embodiment of the invention, the spreading body has an axially parallel or obliquely arranged groove for preventing a rotation between the support cone and the compression sleeve. When the pressing sleeve is pushed onto the support cone, the corrugations of the support cone are pressed into the pressing sleeve and thus form a rotation-preventing mechanism. In principle, the groove can also be provided on the inside of the clamping sleeve. The grooves run axially parallel or obliquely, i.e. have axially parallel sections in the case of an oblique arrangement and thus have a blocking effect which prevents relative movements between the pressure sleeve and the bearing cone in the circumferential direction, i.e. prevents a rotation of the pressure sleeve relative to the bearing cone. The effect of preventing rotation is greater when the grooves are arranged axially parallel, for which purpose the obliquely arranged grooves additionally have a blocking effect against movement in the axial direction, i.e. the obliquely arranged grooves cause the pressure sleeve pushed onto the support cone to stop in the axial direction on the support cone or, conversely, the support cone in the pressure sleeve.

If a component is screwed to the anchored fastening element, the screwing movement exerts a torque on the support cone, in particular during the screwing operation. The corrugation according to the invention increases the torque that can be transmitted from the support cone to the compression sleeve, thus reducing the risk of: the torque applied when fastening the component to the support cone causes the support cone to rotate in the pressure sleeve and thus to be released. In particular, an obliquely arranged groove additionally improves the axial fit of the bearing cone in the pressure sleeve, thus reducing the following risks: the axial force applied during the fastening of the component loosens the support cone and presses it away from the pressing sleeve. This risk is particularly present if the support cone is not supported on the borehole bottom during the anchoring, for example in a through-hole or a deep blind hole during the anchoring.

In a preferred embodiment, the grooves are provided only in an axial section of the support cone, which is located at or near the larger-diameter end of the support cone. The pressing sleeve can thus be pushed onto the support cone with a low force.

According to one embodiment of the invention, the indentations at one or more positions of the circumference of the support cone are suitable as grooves. As a result of the shaping of the recess, sharp-edged ribs or beads are piled up on the side faces of the recess, which are pressed into the pressure sleeves during the displacement of the pressure sleeves and achieve the desired rotation prevention. The notch is simple to produce and the thrust of the compression sleeve is not increased significantly.

Another embodiment of the invention provides straight or oblique knurling on the bearing cone as the grooves. In the case of a beveled knurling, the bevels are arranged in particular in the same direction as the pitch of the fastening thread, although the pitch is normally different. Knurling can also be made simply and inexpensively. The indentations and knurls may be designed such that either one or both are formed on the support cone.

For fastening an object to the fastening element according to the invention, the support cone has a shank, in particular a threaded shank. One embodiment of the invention uses a shank-free support cone which has, for example, an internal thread for screwing in a screw or a bolt. By rodless part is understood: the support cone does not have a shank projecting from the compression sleeve. This embodiment of the invention makes it possible to achieve a countersunk or flush anchoring of the fastening element in a hole. The advantages are that: the shank does not project from a component to which the fastening element is anchored. The grooves according to the invention for preventing rotation between the support cone and the pressure sleeve are advantageous, in particular in the shank-free embodiment of the support cone, but can also be used on support cones having a shank. Of course, the shank-less embodiment of the support cone of the fastening element according to the invention can also be implemented without corrugations, if the rotation prevention by means of corrugations is not used.

One embodiment of the invention uses an anti-loss mechanism which holds the clamping sleeve until the fastening element is anchored to the support cone. This anti-loss mechanism has little meaning after anchoring. The loss prevention mechanism avoids: the compression sleeve and the spreader anchor are separated from one another during storage and transport and hold the compression sleeve in its intended orientation on the support cone. The loss prevention mechanism avoids: the pressing sleeve is mounted upside down on the support cone. It is sufficient for the loss prevention mechanism to hold the clamping sleeve on the support cone against falling out, without a releasable connection being required. The loss prevention means can be, for example, a knurling which holds the clamping sleeve on the support cone with a (small) clamping force.

Claims 15 to 20 are directed towards the anchoring of the previously described fastening element in a hole of a component according to the invention. These claims are explained by the preceding discussion of the fastening element according to the invention.

In order to prevent corrosion, an arrangement according to the invention provides that the clamping sleeve, when the fastening element is anchored in a bore, is, for example, countersunk by approximately 0.5 to 1mm, so that an annular groove surrounding the shank of the fastening element is produced, which groove is located on the rear end face of the clamping sleeve facing away from the support cone. A sealing material is inserted into the circumferential groove according to the invention. If and because the fastening element is composed of another material than the component, the fastening element is anchored in the component. The fastening element and the component form a plating element. In this case, corrosion can also occur if the fastening element and the component are both made of a material which is not inherently rust-resistant, that is to say if, for example, the fastening element consists of a4 steel and the component in which the fastening element is anchored is made of aluminum (in particular, aluminum alloys).

In a further embodiment of the invention, the diameter of the bore into which the fastening element is anchored is approximately sufficient as the anchoring depth, even approximately 2/3 of the diameter of the bore. The diameter of the bore corresponds approximately to the diameter of the undeformed clamping sleeve, and is preferably slightly larger in order to be able to fit the clamping sleeve with clearance into the bore. The small anchoring depth can be achieved independently of the fastening element shank seal.

In order to expand the pressure sleeve so that the fastening element is anchored in a bore, an axial force is exerted on the pressure sleeve, which pushes the pressure sleeve onto the support cone. The method according to the invention with the features of claim 21 introduces a reaction force, which is necessary for applying the axial force, into the shank of the fastening element. I.e. supported on the shank of the fastening element for the application of an axial force. A closed force circuit is created without external forces. The advantages of this structural scheme of the invention are: the fastening element does not have to be supported against the axial force to be applied for pushing the pressure sleeve onto the support cone. A component in which the fastening element is to be anchored, i.e. not necessarily locked in the opposite direction, for anchoring purposes, is to be understood as a component which is a sheet. Furthermore, the fastening element can also be anchored in a deep blind hole or in a through hole by the method according to the invention, since the support cone does not have to be supported on the hole bottom.

According to the invention, the reaction force is introduced into the shank of the fastening element by screwing a nut onto the shank. For this purpose, the shank has to have an external thread. An axial force is applied to the compression sleeve by rotating a nut threaded onto the shank. A compression sleeve may be arranged between the nut and the compression sleeve, which transmits the axial force from the nut to the compression sleeve. If a shank portion without threads is located between the rear end face of the compression sleeve and the nut, the compression sleeve is necessary.

In order to make the fastening element stop against rotation when the nut is screwed onto the shank, a development of the method according to the invention provides that: two lock nuts are screwed onto the shank and tightened against each other. The locking nut can be non-rotatably locked by means of a nut-rotating tool, for example a fork-shaped or ring-shaped wrench.

One embodiment of the invention applies ultrasonic waves to the compression sleeve for pushing it onto the support cone. Applying ultrasound means exciting the compression sleeve with mechanical vibrations in the ultrasonic frequency range. The vibration is preferably axial. The advantages of using ultrasound for anchoring the fastening element are: the sound is small and the load on the bottom of the bolt is small. The latter makes the ultrasonic anchoring method suitable for fastening fastener elements in thin plates without the need for a counter stop (Gegenhalten). For example, a tubular sonotrode, which transmits vibrations from an ultrasonic vibrator to the compression sleeve, is attached to the rear end face edge of the compression sleeve by the shank of the fastening tool.

The setting tool according to the invention with the features of claim 24 can be designed, for example, in the manner of a punch pin, so that a hammer blow can be transmitted to the pressing sleeve of the fastening element, which pushes the pressing sleeve onto a support cone, which is supported, for example, on the bottom of the blind hole. When the pressing sleeve is sunk in the hole, the pressing sleeve can also be loaded by an installation tool. The setting tool according to the invention has a centering rod which engages in the axial bore of the support cone when the setting tool is mounted on the clamping sleeve. The centering bar positions the installation tool on the fastening element and prevents slipping.

A development of the setting tool uses a tubular collar which surrounds the driving-in centering rod and with which the setting tool is mounted on a likewise tubular pressing sleeve. If the pressure sleeve is countersunk in the bore and/or if the support cone projects from the pressure sleeve, the pressure sleeve can be acted upon by the flange.

The present invention will be described in detail below with reference to embodiments shown in the drawings. The attached drawings are as follows:

FIG. 1: a first embodiment of a fastening element according to the present invention;

FIG. 2: the fastening element shown in fig. 1 is anchored in a component according to the invention;

FIG. 3: a second embodiment of a fastening element according to the present invention;

FIG. 4: an axial section through a third embodiment of the fastening element according to the invention, in which the left side shows the unanchored state and the right side shows the anchored state; and

fig. 5 and 6: enlarged views of the details indicated by the arrows V and VI in fig. 4, wherein fig. 5 shows the non-anchored state of the fastening element and fig. 6 shows the anchored state thereof;

FIG. 7: a fourth embodiment of a fastening element according to the invention in the unanchored state;

FIG. 8: a bearing cone and a pressing sleeve of a fifth embodiment of a fastening element according to the invention, shown in side view;

FIG. 9: end view of the support cone according to arrow IX in fig. 8;

FIG. 10: the fastening element shown in fig. 8 is in an assembled state;

fig. 11 to 13: the fastening element shown in fig. 8 is assembled in a sequential manner by means of an installation tool according to the invention.

The inventive fastening element, generally designated 10, shown in fig. 1, has a shank 12 which has a support cone 14 at one end, which flares in the direction away from the shank 12. The fastening element 10 furthermore has a tubular, non-slotted compression sleeve 16, which can be slid onto the shank 12. The pressure sleeve 16 and the shank 12 with the bearing cone 14 are made of a stainless a4 steel, i.e. a harder steel.

The pressure sleeve 16 has a hollow conical expansion 18 in the form of an angle on its end face facing the support cone 14. The angle of taper of the divergent mouth 18 of the hollow, solid-cone shape is smaller than the angle of taper of the support cone 14, which latter angle of taper is approximately 17 °. Due to the different cone angles, if the pressure sleeve 16 is pushed onto the support cone 14, the pressure sleeve 16 is initially supported on the support cone 14 with its end face edge facing the support cone 14. That is to say that when the compression sleeve 16 is pushed onto the support cone 14, the compression sleeve 16 is not supported equally over the entire axial length of its hollow-conical expansion 18 on the support cone 14 with the hollow-conical expansion 18. The pressure sleeve 16 can thus expand slightly radially outward on its end face edge facing the support cone 14 if it is pushed onto the support cone 14. The different cone angles of the hollow conical expansion 18 of the pressure sleeve 16 and of the support cone 14 are exaggerated in the drawing in order to show the different cone angles clearly and the support cone 14 on which the pressure sleeve 16 is supported with its end face edge facing the support cone 14. The difference in the cone angle is illustrated by exaggeration in the figure, in which a larger annular gap is formed between the pressing sleeve 16 and the shank 12 than is illustrated to scale.

The pressure sleeve 16 is provided on its outside with a roughened cross-knurling 20 in an end facing the support cone 14.

Fig. 2 shows a fastening device according to the invention with the aid of the fastening element 10 shown in fig. 1. The fastening element 10 with its support cone 14 is inserted into an initially cylindrical blind hole, without reference numerals, in a component, for example a structural steel plate 22. The clamping sleeve 16 is pushed onto the support cone 14. The pressure sleeve 16 is pushed onto the support cone 14, for example, by means of a tubular setting tool, not shown, which is attached to the end face side of the pressure sleeve 16 facing away from the support cone 14 via the shank 12. The pressing sleeve 16 is pushed onto the support cone 14 by hammering, wherein the displacement is shown to be more precise than the expansion in this case. When pushed onto the support cone 14, the support cone 14 causes the pressure sleeve 16, at its end face edge facing the support cone 14, to begin to expand radially outward in the end facing the support cone 14. Due to its greater rigidity, the compression sleeve 16 is pressed into the originally cylindrical and undercut-free hole wall in the end of the support cone 14 and anchors the fastening element 10 in the structural steel plate 22 in a positive-fit and non-positive-fit manner. When the compression sleeve 16 is expanded, the cross-knurls 20 also press into the hole walls in the structural steel plate 22 and improve the anchoring of the fastening element 10 in the structural steel plate 22.

An anchoring method according to the invention displaces the compression sleeve 16 onto the support cone 14 by applying ultrasonic load to the compression sleeve 16. For this purpose, as shown in fig. 2 by dashed lines, a tubular sonotrode 23 is shown, which is attached to the rear end face of the compression sleeve 16 via the shank 12. The sonotrode 23 is excited by an ultrasonic vibrator, not shown, for generating axial vibrations in the ultrasonic frequency range and transmitting the vibrations to the compression sleeve 16. The compression sleeve 16 is thus pushed over the support cone 14 and expanded, that is to say spread open, and the fastening element 10 is anchored in the structural steel plate 22. The use of ultrasonic waves for low sound expansion and low loading of the structural steel plate 22 eliminates the need for a bracket to support the structural steel plate 22.

If the blind hole in the structural steel plate 22 has a defined depth, the anchoring of the fastening device 10 is terminated when the clamping sleeve 16 is sunk flush in the structural steel plate 22. In this way it is easily possible to determine whether the fastening element 10 is correctly anchored.

The compression sleeve 16 supports the fastening element 10 against lateral loads. It must be considered that: the annular gap between the compression sleeve 16 and the shank 12 is exaggerated in the figures.

A method of fastening a further component, not shown, to the structural steel plate 22 is provided in a simple manner with the fastening means shown in fig. 2. To secure one such other component, the shank 12 is provided with threads 24. In addition to the thread 24 or instead of the thread 24, the shank 12 can have an axial blind hole 26, through which the free end of the shank 12 can be flanged outwards for forming a riveted connection (not shown). A mating pin having a head may also be pushed into blind hole 26 to secure another component to structural steel plate 22 (not shown). Alternatively, the blind bore 26 is internally threaded.

The fastening element 10 requires only a small anchoring depth. The diameter of the blind hole in the structural steel plate 22 is 8mm when the blind hole depth is 5-6mm when the diameter of the shank 12 threads 24 is M6. The shank diameters of the fastening elements 10 of one standardized series of structures are 4, 5, 6, 8 and 10mm, or the thread diameters 24 are M4, M5, M6, M8 and M10. The wall thickness of the compression sleeve is 1mm, and when the diameter is more than M8, the wall thickness can also be 1.5 mm. The outer diameter of the compression sleeve 16 and the outer diameter of the hole in the structural steel plate 22 are thus 6, 7, 8, 10 or 11 and 12 or 13mm for a given diameter. The corresponding minimum anchoring depth t is 3.5mm when the thread diameter is M4, 4.0mm when the thread diameters are M5 and M6, 6.0mm when the thread diameter is M8, and 7.0mm when the thread diameter is M10.

The fastening element 10 according to the invention shown in fig. 3 has an annular step 15 at the transition from the shank 12 to the support cone 14, at which the support cone 14 transitions to a smaller diameter of the shank 12. The support cone 14 also has a larger diameter than the shank 12 at its smaller diameter end facing the shank 12. The support cone 14 is therefore axially shorter than a support cone of the same diameter and of the same cone angle on the bottom side facing away from the shank 12. The fastening element 10 shown in fig. 3 is also designed identically to that shown in fig. 1, see the description of fig. 1 and 2.

The fastening element 10 according to the invention shown in fig. 4, like the two previously described fastening elements 10, has a shank 12 with a support cone 14 at one end, which widens in the direction away from the shank 12.

The pressure sleeve 16 has an inner support cone 18 which flares in the same direction as the support cone 14, i.e. in the direction of the support cone 14. The inner support cone 18 is axially longer than the hollow conical expansion 18 of the compression sleeve 16 of the fastening element 10 described above. The inner support cone 18 passes through the compression sleeve 16 over a substantial portion of its axial length. The cone angle of the inner support cone 18 is smaller than the cone angle of the support cone 14, which is about 17 °. Due to the difference in the angle of taper, when the clamping sleeve 16 is pushed onto the support cone 14, it is first pushed onto the support cone 14 with its end face edge facing the support cone 14. This can be seen in the left side of fig. 4 and in the enlarged view of fig. 5, both of which represent the unanchored state. When the pressure sleeve 16 is pushed onto the bearing cone 14, the pressure sleeve 16 is thus supported, not identically, over its entire axial length on the bearing cone 14 by its inner bearing cone 18. It is therefore easier to expand the pressure sleeve 16 radially outward at its end face edge facing the support cone 14 if it is pushed onto the support cone 14.

The right-hand side of fig. 4 and the enlarged illustration of fig. 6 show a fastening device according to the invention with a fastening element 10, i.e. the anchoring of the fastening element 10. The support cone 14 of the fastening element 10 is inserted into an initially cylindrical blind hole of a component, for example a structural steel plate 22, without reference numerals. The clamping sleeve 16 is pushed onto this support cone 14.

Another option for expanding the compression sleeve 16 is to: a pipe section, not shown, is placed on the shank 12 and a nut, also not shown, is screwed onto the thread 24 of the shank 12. An axial force is exerted on the compression sleeve 16 by the pipe nut, which pushes the compression sleeve 16 onto the support cone 14 and expands it, and thus anchors the fastening element 10 in the hole in the structural steel plate 22 in the manner described above. The advantages of this anchoring method are: no external forces act, i.e. the fastening element 10 does not have to be supported on the bottom of the hole to which it is to be anchored, and the fastening element 10 does not have to be supported against the axial force exerted on the compression sleeve 16 for expansion. The structural steel plate 22 therefore does not have to be supported, as is the case when the compression sleeve 16 is expanded by hammering. Furthermore, the described anchoring method makes it possible to achieve anchoring in a deep blind hole, in which the fastening element 10 is not supported on the hole bottom, or in a through hole.

In order to seal the holes in the structural steel plate 22 and to press the pressure sleeve 16, as can be seen from the right in fig. 1, it is embedded in the structural steel plate 22, for example, by approximately 0.5 to 1 mm. This forms an annular groove 26 which surrounds the shank 12 of the fastening element 10 and is filled with a sealing material 28.

The support cone 14 with shank 12 and the pressure sleeve 16 of the fastening element 10 shown in fig. 7 correspond to the embodiment shown in fig. 1. Reference is made to the above description. On the larger diameter side of the support cone 14 facing away from the shank 12, the shank 12 or the support cone 14 has an axial extension 23. The extension 23 is cylindrical and has the same diameter as the larger diameter end of the support cone 14. The extension 23 is axially short and it has only a small portion of the length of the support cone 14 in the axial direction. The support cone 14 is axially shorter than the shank 12 diameter. The axial extension 23 terminates with an edge 25. An axially parallel, raised anti-rotation rib 27 prevents the shank 12 and the bearing cone 14 from rotating in the compression sleeve 16.

The axial extension 23, when the pressure sleeve 16 is displaced, supports the support cone 14 on the borehole bottom 29, which keeps the support cone 14 at a distance from the borehole bottom 29. An axial free space is thus formed between the pressure sleeve 16 and the bottom 29 of the borehole, the pressure sleeve 16 not bearing against the bottom 29 of the borehole when it is pushed onto the bearing cone 14. The expansion of the compression sleeve 16 is not hindered by the bottom 29 of the borehole.

The fastening element 10 according to the invention shown in fig. 8 and 9 has a support cone 12 and a pressure sleeve 14. Both consist of a high-hardness steel, in particular an alloyed stainless steel (e.g. a 4-steel). The support cone 12 has a cylindrical portion 30 outside the support cone at the small-diameter end of the support cone, and the support cone 12 has a coaxial through-bore with an internal thread 32. At the larger-diameter end of the support cone 12, an axially shorter section is provided with an oblique or linear knurling 34, in the figure a linear knurling. Furthermore, axially parallel recesses 36 are formed at two mutually opposite locations on the circumference of the support cone 12, which recesses form on their side faces pointed ribs 38 projecting outward from the support cone 12. The notch 36 begins at the larger diameter end of the support cone 12 and ends axially approximately in the middle of the support cone 12.

The non-slotted compression sleeve 14 has a through-opening 40 which is complementary to the support cone 12 and its cylindrical section 16, i.e. the through-opening 40 of the compression sleeve 14 has a cylindrical section 42 and a support cone-shaped section 44, the diameters of which correspond to the diameters of the support cone 12 and its support cylinder-shaped section 30, respectively. The holding-down sleeve 14 has a circumferential cross-knurling 20 on the outside, which extends from the front end of the holding-down sleeve 14 over an axial section that is shorter than the supporting conical section 44 of the through-opening 40. The cross knurls 20 are pressed into the hole wall during the anchoring process as described above and thus improve the anchoring of the fastening element 10 by means of a positive connection.

The knurling 46 on the cylindrical section 30 of the support cone 12 clamps the clamping sleeve 14 against falling off onto the support cone 12. The knurling 46 forms a loss prevention mechanism of the compression sleeve 14 on the support cone 12, which does not prevent the compression sleeve 14 from being pushed onto the support cone 12.

Fig. 10 shows a fastening element 10 consisting of a support cone 12 and a compression sleeve 14. The axial length of the fastening element 10 is of the same order of magnitude as its outer diameter, and the fastening element 10 is therefore axially shorter than its diameter and can be anchored in a short undercut-free blind hole.

The support cone 12 of the fastening element 10 shown in fig. 8 to 10 is shank-free, that is to say it has no threaded shank or the like for fastening a component, and the internal thread 32 for fastening a component.

For anchoring in a component, for example an aluminum plate 48, the fastening element 10 is inserted into a hole 50 in the aluminum plate 48, with the support cone 12 bearing on the base of a drilled hole or, in the exemplary embodiment shown, on an annular (support cone-shaped) shoulder 52 of the hole 50 (fig. 11). The compression sleeve 14 is pushed onto the support cone 12 and thus expands at least in the region of the support cone. The compression sleeve 14 expands by being pushed onto the support cone 12, which can also be referred to as spreading. The clamping sleeve 14 is thus pressed against the hole wall, the cross-knurls 20 of which are formed in the hole wall, so that the fastening element 10 is anchored in the hole 50 by means of a force-fit connection and a friction-fit connection (fig. 12). Since the support cone 12 is shank-free, the fastening element 10 does not project beyond the aluminum plate 48.

For the displacement of the compression sleeve 14 onto the support cone 12, a setting tool 54 according to the invention, which is shown in fig. 11 and 12, is provided. The tool 54 is a cylindrical steel pin with a diameter corresponding to the diameter of the compression sleeve 14. The installation tool 54 has an axial centering rod 56 and a tubular flange 58 surrounding the centering rod 56. The diameter of the centering rod 56 is not greater than the inner diameter of the internal threads 32 of the support cone 12. When the setting tool 54 is placed on the compression sleeve 14, the centering rod 56 enters the internal thread 32 and thus positions the tool 54 on the fastening element 10. The setting tool 54 is supported with this flange 58 on one end face of the compression sleeve 14. The outer and inner diameters of the flange 58 correspond to the outer and inner diameters of the compression sleeve 14. The pressure sleeve 14 is pushed onto the support cone 12 by hammering on the setting tool 54 placed on the pressure sleeve 14. This displacement may be referred to as dilation. The compression sleeve 14 can be anchored in the hole 50 by means of the setting tool 54 in a sunk manner, without the fastening element 10 projecting beyond the aluminum plate 48.

The fastening of a component, for example a profile steel 60, to the fastening element 10 anchored in the hole 50 in the aluminum plate 48 is effected, for example, by means of a screw 62 which passes through the profile steel 60, the screw 62 being screwed into the internal thread 32 of the support cone 12. When tightened, the screw 62 pulls the support cone 12 deeper into the compression sleeve 14, so that the compression sleeve 14 is expanded even more and the anchoring is even stronger. The knurls 20 of the support cone 12 and the recesses 36 with the ribs 38 are pressed into the pressure sleeve 14 when the pressure sleeve 14 is pushed onto the support cone 12 or, conversely, when the support cone 12 is pulled into the pressure sleeve 14, and they form an anti-rotation mechanism which prevents the support cone 12 from rotating and thus loosening in the pressure sleeve 14 when the screw 62 is screwed in.

A stepped configuration of the bore 50 is used in accordance with the present invention. The bore 50 has an anchoring section 64, the diameter of which is equal to the diameter of the compression sleeve 14, in which the fastening element 10 is anchored. The annular shoulder 52 reduces the diameter of the bore 50 or an axial extension 66, which is at least as large as the outer diameter of the internal thread 32 of the support cone 12 or of the thread of the threaded part 62. The extension 66 of the bore 50 allows the screw 62 to be screwed through the support cone 12 without the screw 62 bearing on the bottom of the bore and the fastening element 10 being loaded in the direction out of the bore 50. The advantages of the structure scheme of the invention are that: a threaded member 62 of in principle any length may be applied.

Claims (16)

1. Fastening element for anchoring in a short, undercut-free blind hole, comprising a shank (12) with a support cone (14) at one end, which expands in the direction away from the shank (12), and an undercut, tubular pressing sleeve (16), through which the shank (12) can be pushed onto the support cone (14) for expanding and anchoring in the blind hole, so that it expands on an end facing the support cone (14), characterized in that the pressing sleeve (16) has a hollow-conical expansion (18) on its inner side facing the end face of the support cone (14), the hollow-conical expansion (18) of the pressing sleeve (16) having a smaller cone angle than the cone angle of the support cone (14), and the pressing sleeve (16) has a pressing cone (14) on its outer side at its end facing the support cone (14) A hair portion (20).

2. The fastening element as claimed in claim 1, characterized in that the cone angle of the support cone (14) is 14 ° to 20 °.

3. The fastener of claim 2 wherein said support cone has a cone angle of about 17 °.

4. The fastening element as claimed in claim 1, characterized in that the fastening element (10) comprises a high-hardness steel at least on the outside in the end of the compression sleeve (16) facing the bearing cone (14).

5. The fastening element as claimed in claim 1, characterized in that the diameter of the support cone (14) at the transition to the shank (12) is greater than the diameter of the shank (12); furthermore, the support cone (14) transitions with an annular step (15) to the smaller diameter of the shank.

6. The fastening element according to claim 1, characterized in that the pressing sleeve (16) is axially short and has a pressing region which extends over more than half the axial length of the pressing sleeve (16).

7. The fastening element according to claim 1, characterized in that the fastening element (10) has a thin-walled compression sleeve (16).

8. The fastening element as claimed in claim 1, characterized in that the shank (12) has an axial projection (23) on a side of the support cone (14) facing away from the shank (12) for supporting the support cone (14) on the base (29) of the blind hole when the pressing sleeve (16) is pushed in.

9. The fastening element as claimed in claim 8, characterized in that the projection (23) does not project laterally beyond the support cone (14).

10. The fastening element as claimed in claim 1, characterized in that the bearing cone (14) has an axially parallel or obliquely arranged corrugation (34, 36, 38) for preventing rotation between the bearing cone (14) and the pressing sleeve (16).

11. The fastening element as claimed in claim 1, characterized in that the support cone (14) is shank-free and has a loss prevention means (21) for retaining the clamping sleeve (16) on the support cone (14).

12. Device with a fastening element (10) which is anchored in an undercut-free bore of a component (22), wherein the fastening element (10) has a shank (12) with a support cone (14) which expands in the direction away from the shank (12), and an undercut clamping sleeve (16) which is pushed onto the support cone (14) in the bore of the component (22) in such a way that the clamping sleeve (16) expands in an end facing the support cone (14) and is pressed into the bore wall of the bore of the component (22), characterized in that the clamping sleeve (16) has a hollow-conical expansion opening (18) on the inner side of its end face facing the support cone (14), and in that the clamping sleeve (16) bears against a part of the axial length of its hollow-conical expansion opening or against a part of the axial length of the support cone On the support cone (14), the pressing sleeve (16) has a roughening (20) on its outer side at its end facing the support cone (14).

13. Device according to claim 12, characterized in that the compression sleeve (16) has a greater hardness than the component (22) at least on the outside in its end facing the support cone (14) and pressed into the bore wall of the component (22).

14. Device according to claim 12, characterized in that the anchoring depth of the fastening element (10) in the bore of the component (22) is not greater than, but smaller than, the diameter of the bore.

15. Device according to claim 12, characterized in that the pressing sleeve (16) is countersunk in the bore of the component (22), and an annular groove (26) which is formed by the countersunk pressing sleeve (16) and which surrounds the shank (12) is provided with a sealing material (28).

16. The device as claimed in claim 12, characterized in that the support cone (14) is shank-free and has an internal thread (32); the bore (50) in the component (48) is stepped and has an anchoring section (64) which has a diameter corresponding to the outer diameter of the compression sleeve (16) and in which the support cone (14) and the compression sleeve (16) are anchored; furthermore, the bore (50) has an axial extension (66) which has a diameter which is smaller than the diameter of the anchoring section (64) and which is at least as large as the outer diameter of the internal thread (32) of the bearing cone (14).