Fixing element for reinforcement connection with a secondary action, especially for earthquake-resistant securement

A fixing element providing a reinforcement connection with a secondary action and settable in a drill hole by a hardenable composition the fixing element has a reinforcement rod, and at least one conical sleeve provided on the reinforcement rod, the at least one conical sleeve having a segment-shaped construction.

BACKGROUND OF THE INVENTION
 The present invention relates to fixing elements for reinforcement
 connection with a secondary action, especially for earthquake-resistant
 securement.
 Reinforcement rods are frequently used to strengthen building structures
 using a hardenable composition in the drill hole. It has proved a
 disadvantage that, during the lifetime of the fixing, large cracks occur
 in the concrete, especially in the event of shock loading, such as during
 an earthquake, and the anchoring can fail.
 Fixing elements are known which consist substantially of a threaded bolt,
 an expansible sleeve and an expander body with expander cone that can be
 drawn into the expansible sleeve. The expansible sleeve has longitudinal
 slots, which allow the expansible sleeve to expand as the expander body is
 drawn in. These fixing elements are generally set in an undercut drill
 hole with which the expanded sleeve forms an interlocking fit.
 European patent document EP 0 455 952 Bi describes a fixing element for
 fixing in a substrate affected by momentary shock loading, such as that
 occurring during an earthquake. To avoid failure of a fixing in the event
 of shock loading, in this case a bolt and a complementary expansible
 sleeve are proposed. The expansible sleeve has two expanding portions, the
 first cylindrical portion having the smallest diameter of the expander
 cone and a second conically widening portion having the largest diameter,
 the continuation of which is cylindrical. It has proved to be a
 disadvantage of the known fixing element that in the event of shock
 loading considerable axial slippage occurs, and the component becomes
 loose, so that a new fixing element has be used following the overloading.
 Furthermore, mounting in an undercut is complicated, because the undercut
 has to be prepared, and for many applications is too expensive.
 An anchor stud for a synthetic resin adhesive is known, having a shank that
 has several cones arranged in the axial direction european patent document
 (EP 0 356 425). This known anchor stud is set in the drill hole by means
 of a hardenable composition. This known anchor stud is not suitable as a
 replacement for a reinforcement rod, since only the proper standardized
 reinforcement rods permit a reinforcement connection.
 SUMMARY OF THE INVENTION
 The invention is based on the problem of producing a fixing element for a
 reinforcement connection with a secondary action, especially for
 earthquake resistant securement, which can be manufactured economically
 and permits uncomplicated and secure anchoring.
 In keeping with these objects and with others which will become apparent
 hereinafter, one feature of present invention resides, briefly stated, in
 a fixing element for reinforcement connection with a secondary action,
 which element is set in a drill hole by means of a hardenable composition,
 wherein in accordance with the inventive feature, the reinforcement rod is
 provided with one or more conical sleeves, and the conical sleeves are of
 a segment-shaped construction.
 Because the reinforcement rod is provided with one or more conical sleeves,
 and the annular gap between the drill hole wall and the reinforcement rod
 is filled with a hardenable composition, when subjected to shock loading
 the hardened mortar shell is pressed by the conical sleeve against the
 drill hole wall and the anchoring is maintained. The construction of the
 reinforcement rod according to the invention and mounting thereof by means
 of a hardenable composition provides a system for a reinforcement
 connection that withstands cracks, with which different anchoring depths
 are possible. To facilitate sliding of the conical sleeve in the mortar
 shell, a dry film can be disposed on the surface of the segments.
 In the event of sustained shock loading, cracks occur in the concrete. To
 ensure a safe reinforcement connection in this case, the reinforcement rod
 is additionally provided in its upper region with a plastics material
 sleeve, so that a non-adhering, low-friction surface is produced and the
 reinforcement rod is able to slide up subsequently as required, and the
 mortar shell formed is pressed by the conical sleeve against the wall of
 the drill hole. This embodiment is especially suitable for reinforcement
 connections having relatively short anchoring depths. Instead of a
 plastics material sleeve, the reinforcement rod can be provided with a
 coating agent. Coatings of wax-like synthetic polymer,
 polytetrafluoroethylene, silicone polymer or galvanically applied
 coverings have proved suitable. An other option is to sheathe the
 reinforcement rod in a deep-drawn, rigid plastics material sleeve. Other
 means can also be employed to achieve the low friction value.
 For prolonged shock loading, the formation of cracks is additionally
 accompanied by damage to the concrete as well, so that parts of the
 concrete, particularly in the upper region, break off. In that case, a
 longer anchoring depth is recommended. The segment-form construction of
 the conical sleeve enables reinforcement rods of different diameter to be
 used.

DESCRIPTION OF PREFERRED EMBODIMENTS
 A fixing element according to the invention illustrated in FIG. 1 has a
 reinforcement rod 1, with a profiling 2, on which a conical sleeve 3 is
 mounted. The conical sleeve 3 consists of two or more segments 5, 6 which
 are held together in each of the lower and upper regions by a respective
 ring or adhesive band 7. It is also possible for several conical sleeves
 to be arranged on the reinforcement rod. The conical sleeves 3 are
 positioned on the reinforcement rod 1 by locking a profiled inside 8 of
 the segment onto the reinforcement rod 1, as illustrated by FIGS. 3 and 4.
 The reinforcement connection with secondary action is effected in that,
 after making and cleaning the drill hole a hardenable composition is
 injected into the drill hole and the reinforcement rod 1 is inserted into
 the composition. As this is done, the composition rises towards the mouth
 of the drill hole, so that the entire annular gap 16 is filled with
 composition 12, as shown in FIG. 4.
 When cracks occur, the conical sleeves press the mortar shell against the
 drill hole wall, so that subsequent expansion by the reinforcement rod is
 able to occur and the anchoring is maintained.
 The fixing element shown in FIG. 5 consists of a reinforcement rod 12
 having a profiling 2, on which two conical sleeves 3 are mounted. The
 conical sleeves 3 consist of conical segments 5, 6, which are held
 together in each of the upper and lower regions by means of a respective
 ring or adhesive band 7. The reinforcement rod is provided in the upper
 region with plastics material. sleeve 132 which ensures that a bond-free
 region when the reinforcement rod 1 is cemented into the hardenable
 composition 12. Positioning of the conical sleeve 3 on the reinforcement
 rod 1 is effected by locking the profiled inside 8 of the conical segment
 onto the reinforcement rod 1. The inner profiling 8 of the segment can
 achieved by knurling; or applying corrugations or threads.
 The reinforcement connection with secondary action is effected as follows:
 after making a drill hole in a substrate and cleaning the hole, the
 hardenable composition 12 is injected into the drill hole and the
 reinforcement rod its inserted. As the annular gap 16 fills with
 hardenable composition 12, in the region of the plastics material sleeve
 13 located on the reinforcement rod a bondAree area remains, so that
 during protracted loading the reinforcement rod is able to slide up
 subsequently. As it does so, the mortar shell is pressed against the drill
 hole wall and the anchoring is maintained. By virtue of the segment-form
 construction of the conical sleeve 3, reinforcement rods of different
 diameters can be used with the conical sleeve.
 It will be understood that each of the elements described above, or two or
 more together, may also find a useful application in other types of
 constructions differing from the types described above.
 While the invention has been illustrated and described as embodied in a
 fixing element for reinforcement connection, it is not intended to be
 limited to the details shown, since various modifications and structural
 changes may be made without departing in any way from the spirit of the
 present invention.
 Without further analysis, the foregoing will so fully reveal the gist of
 the present invention that others can, by applying current knowledge,
 readily adapt it for various applications without omitting features that,
 from the standpoint of prior art, fairly constitute essential
 characteristics of the generic or specific aspects of this invention.