the embodiments of fig3 and 4 wedge like recesses 274 are provided at a total of eight positions around the peripherally extending contact surface 242 of the element and are produced by a cold heading process these recesses 274 produce noses 276 which project radially into the ring recess 218 and form the undercuts 225 at the corresponding positions in the outer side wall 224 of the ring recess 218 during the installation process the material of the sheet metal part 216 is deformed both into the wedge shaped recesses 274 and also into the regions 278 between the noses 276 whereby an enhanced security against rotation is produced relative to the previous embodiments the undercuts are fully sufficient in order to generate a comparable press out resistance since the undercuts are not formed by the production of an inclined flank 54 and 154 in the previous examples the contact surface 242 is substantially greater in the examples of fig3 and 4 than in the previous examples this improvement achieves lower surface pressures in operation or permits the use of hollow elements with softer sheet metals however the outer dimensions of the hollow element 210 can also be reduced relative to the previous embodiments without concern regarding the loss.