FIXING ELEMENT

Abstract

A fixing element is provided for anchoring in a drilled hole. The fixing element extends along a longitudinal axis and has a shank on which an expansion sleeve is arranged. On the shank there is also arranged a holding element by which the expansion sleeve is connected by frictional engagement to the shank so as to be fixed against relative rotation.

Claims

1. A fixing element for anchoring in a drilled hole, wherein the fixing element extends along a longitudinal axis and has a shank having a load-application means, a neck portion and an expander bod, wherein on the neck portion there is arranged an expansion sleeve which is expansible radially by drawing the expander body into the expansion sleeve, and wherein on the shank there is arranged a holding element which is resiliently deformable to modify its diameter and which has an opening in which the shank is accommodated, wherein the holding element is compressible by radial pressure in a way that the external diameter of the holding element is larger than the external diameter of the unexpanded expansion sleeve and the internal diameter of the holding element is the same as the diameter of the part of the shank on which the holding element is arranged, in a way that the holding element is connected by frictional engagement to the shank so as to be fixed against relative rotation.

2. The fixing element according to claim 1, wherein the holding element has an annular or sleeve-like wall having at least one weakened position.

3. The fixing element according to claim 1, wherein the shank is in one piece.

4. The fixing element according to claim 1, wherein on the holding element there is arranged at least one connecting element for connection to the expansion sleeve.

5. The fixing element according to claim 1, wherein radially outwardly extending projections are arranged on the holding element.

6. The fixing element according to claim 2, wherein the projections are movable resiliently into receiving spaces in the wall of the holding element.

7. The fixing element according to claim 1, wherein the expansion sleeve comprises a plurality of individual expansion shells which are not integrally connected to one another.

8. The fixing element according to claim 1, wherein the expansion sleeve is surrounded by an annular spring.

9. The fixing element according to claim 8, wherein the annular spring is located in a groove which is formed in the circumferential direction on the expansion sleeve.

10. The fixing element according to claim 7, wherein the expansion sleeve is surrounded by an annular spring, the annular spring is located in a groove which is formed in the circumferential direction on the expansion sleeve, and the groove is formed on the expansion shells in a region of the expansion shells that has a reduced width in the circumferential direction.

11. The fixing element according to claim 4, wherein the expansion sleeve is surrounded by an annular spring and the connecting element is connected to the annular spring.

12. The fixing element according to claim 1, wherein the load-application means is an external thread which extends as far as the end of the fixing element that is at the rear in the introduction direction.

13. The fixing element according to claim 1, wherein the expansion sleeve in the unexpanded state has an external diameter that is smaller than the nominal diameter of the fixing element.

Description

[0016] The invention is explained in greater detail below with reference to two exemplary embodiments which are shown in the Figures, wherein

[0017] FIG. 1 is a side view of a first fixing element according to the invention;

[0018] FIG. 2 is a perspective view of the expansion sleeve and the holding element of the fixing element of FIG. 1;

[0019] FIG. 3 shows a section through the fixing element in the plane III-III;

[0020] FIG. 4 shows a section through the fixing element in the plane IV-IV;

[0021] FIG. 5 is a side view of the second fixing element according to the invention;

[0022] FIG. 6 is a perspective view of the expansion sleeve and the holding element of the fixing element of FIG. 3; and

[0023] FIG. 7 is a perspective view of an expansion shell of the expansion sleeve of the second fixing element according to the invention.

[0024] FIGS. 1 to 4 show a first fixing element 1 according to the invention for anchoring in a drilled hole (not shown). The fixing element 1 extends along a longitudinal axis L from an end 2, which is at the front in the introduction direction E, to a rear end 3 of the fixing element 1. The fixing element 1 is implemented as a bolt anchor having an elongated, peg-like shank 4 of one-piece construction. Starting from the rear end 3, an external thread 5 is provided on the shank 4 as load-application means, which external thread is adjoined in the introduction direction E by a cylindrical spacer portion 20. The external thread 5 extends as far as the rear end 3 of the fixing element 1. In front of the spacer portion 20 in the introduction direction E there is arranged a neck portion 6 which is likewise cylindrical with a diameter D which is, however, smaller than the diameter DD of the spacer portion 20. The neck portion 6 is adjoined in the introduction direction E by an expander body 7, forming the front portion of the shank 4, which has a conical expansion portion 22 which widens in diameter in the introduction direction E.

[0025] On the neck portion 6 there is arranged an expansion sleeve 8 consisting of three individual expansion shells 9 which are curved in the circumferential direction and in cross-section form parts of a circular ring, as can be seen in FIG. 3. The expansion shells 9 are not connected to one another, especially not integrally. At the rear ends of their longitudinal edges the expansion shells 9 are chamfered, so that there are triangular recesses 13 between the expansion shells. The three expansion shells 9 are held on the neck portion 6 of the shank 4 by a rubber ring 10 acting as annular spring 23, which rubber ring is located in a groove 18. The expansion shells 9 are held against the neck portion 6 by the rubber ring 10 in such a way that their inner sides are in surface-to-surface contact with the neck portion 6 (see FIG. 3). A holding element 12 is arranged between the expansion sleeve 8 and the transition from the neck portion 6 to the spacer portion 20, which transition is in the form of an annular step 11.

[0026] The holding element 12 has a sleeve-like wall 14 having an axial slot 15 as weakened position. As a result of the slot 15, the wall 14 forms an open circular ring having an opening 16 for receiving the neck portion 6 of the shank 4, as can be seen in FIG. 4. At its rear end in the introduction direction E, the holding element 12 is formed so as to lie flat against the annular step 11. At its front end, three pin-like connecting elements 17 are formed as projections 21 on the wall 14, which projections are uniformly distributed around the circumference of the wall 14 and engage in the triangular recesses 13 of the expansion sleeve 8 and connect the expansion sleeve 8 to the holding element 12 so as to be fixed against relative rotation. In the outer surface of the wall 14 there are formed rectangular receiving spaces 19, at the front ends of which there are arranged radially outwardly extending projections 21. The projections 21 are formed integrally with the wall 14 from plastics and are resiliently connected to the wall 14. The projections 21 extend radially outwards in such a way that they define the external diameter D.sub.HA of the holding element 12 (see FIG. 4).

[0027] The expansion shells 9 form the expansion sleeve 8 which, in an unexpanded state, has an external diameter D.sub.S that is smaller than the nominal diameter of the fixing element 1. The nominal diameter of the fixing element 1 is the same as the nominal diameter of the drill to be used to drill the hole into which the fixing element 1 is to be introduced. For example, for a 10 mm drilled hole a 10 mm drill is used and the nominal diameter of the fixing element 1 is 10 mm, even though the actual diameter of the fixing element 1 may differ therefrom. In the case of the fixing element 1 according to the invention, the external diameter D.sub.S of the expansion sleeve 8 is smaller than the nominal diameter of the fixing element 1 and is 9.8 mm. The holding element 14, however, as a result of the projections 21, has an external diameter D.sub.HA that is larger than the nominal diameter. That external diameter D.sub.HA is defined by the projections 21 and is accordingly modifiable by resilient deformation.

[0028] When the fixing element 1 is inserted as intended into a drilled hole of a nominal diameter, the expansion sleeve 8 does not impede insertion, so that the fixing element 1 can be pushed or inserted into the drilled hole without a large amount of force, especially without using a hammer. During insertion, the radially outwardly extending projections 21 fold at least to some extent resiliently into the receiving space 19. The projections 21 rest with their radially outer, free ends in contact with the wall of the drilled hole and are pressed resiliently against the wall of the drilled hole in such a way that the wall of the drilled hole compresses the holding element 12 radially so that the slot 15 closes slightly and the internal diameter D.sub.HI of the holding element 12 corresponds to the diameter D of the neck portion 6. The external diameter D.sub.HA of the holding element 12 is accordingly larger than the external diameter D.sub.S of the unexpanded expansion sleeve 8 and the internal diameter D.sub.HI of the holding element 12 is the same as the diameter D of the neck portion 6. As a result of the radial pressure exerted on the holding element 12 by the wall of the drilled hole, the holding element 12 rests closely against the neck portion 6 so that, by virtue of the friction between the holding element 12 and the neck portion 6, the holding element 12 is connected by frictional engagement to the shank 4 so as to be fixed against relative rotation. The frictional action impedes displacement of the shank 4 in the axial direction relative to the holding element 12 and to the expansion sleeve 8 only negligibly and can be overcome by tightening a nut (not shown) screwed onto the external thread 5. However, the friction acting between the nut and the external thread 5 when the nut is screwed on is insufficient to overcome the friction of the connection that that fixes the neck portion 6 and the holding element 12 against relative rotation and so the shank 4 would corotate with the nut. Because the shank 4 is connected to the holding element 12 so as to be fixed against relative rotation, the shank 4 is prevented from corotation when a nut is screwed onto the external thread 5. When the nut is tightened, the shank 4 is moved out of the drilled hole in a direction opposite to the introduction direction E. As a result of the holding element 12, which is resiliently clamped by its projections 21 against the wall of the drilled hole, the expansion sleeve 8 remains in fixed position in the drilled hole and the expander body 7 with its conical expansion portion 22 is drawn into the expansion sleeve 8, with the result that the expansion shells 9 are expanded radially. The friction between the holding element 12 and the shank 4 is overcome by the force acting in the axial direction, whereas the force acting in the circumferential direction as a result of screwing on the nut is insufficient to cancel the connection that fixes the holding element 12 and the shank 4 against relative rotation.

[0029] FIGS. 5 to 7 show a second fixing element 101 according to the invention, the shank 104 of which is constructed in the same way as the shank 4 of the fixing element 1 of FIGS. 1 to 4. To avoid repetitions, only the differences from the fixing element 1 of FIGS. 1 to 4 will be discussed below. The fixing element 101 likewise has a holding element 112, the structure of which corresponds to that of the holding element 12 of the first fixing element 1 according to the invention. However, the projections 121 acting as connecting elements 117, which projections are arranged on the introduction-side front end of the wall 114, are integral with a slotted annular spring 123 running in the circumferential direction, which spring engages in grooves 118 of the expansion shells 109. In this case the expansion shells 109 are connected to the holding element 112 so as to be both fixed against relative rotation and axially fixed. The grooves 118 are formed in a rear region of the expansion shell 109, which region has a width BR, measured in the circumferential direction, that is reduced relative to the width B of the region of the expansion shell 109 that is at the front in the introduction direction E, with the result that the groove 118 can be stamped into the material more easily than in the front region of the expansion shell 109.

[0030] By virtue of their configuration according to the invention, the fixing elements 1, 101 according to the invention shown in the Figures can be introduced into a drilled hole using very little axial force. A particular advantage is that it is usually unnecessary to use a hammer to drive the fixing elements 1, 101 into a drilled hole. The fixing elements 1, 101 are of simple construction and consist of relatively few, easily assembled parts and they are therefore economical to produce.

LIST OF REFERENCE SIGNS

Fixing Element

[0031] 1, 101 fixing element [0032] 2, 102 front end of the fixing element 1, 101 [0033] 3, 103 rear end of the fixing element 1, 101 [0034] 4, 104 shank [0035] 5, 105 external thread [0036] 6, 106 neck portion [0037] 7, 107 expander body [0038] 8, 108 expansion sleeve [0039] 9, 109 expansion shell [0040] 10 rubber ring [0041] 11, 111 annular step [0042] 12, 112 holding element [0043] 13 triangular recess [0044] 14, 114 wall [0045] 15, 115 slot [0046] 16, 116 opening [0047] 17, 117 connecting element [0048] 18, 118 groove [0049] 19, 119 receiving space [0050] 20, 120 spacer portion [0051] 21, 121 projection [0052] 22, 122 conical expansion portion [0053] 23, 123 annular spring [0054] B width of an expansion shell 9, 109 [0055] B.sub.R reduced width of an expansion shell 109 [0056] D diameter of the neck portion 6 [0057] D.sub.D diameter of the spacer portion 20 [0058] D.sub.HA external diameter of the holding element 12 [0059] D.sub.HI internal diameter of the holding element 12 [0060] D.sub.S external diameter of the unexpanded expansion sleeve 8 [0061] E introduction direction [0062] L longitudinal axis