Abstract: The invention relates to inorganic-organic compound substances useful for biomedical purposes. The object of the invention is to develop inorganic-organic compound materials which overcome the disadvantages of the state of art, wherein inorganic-organic compound substances for biomedical purposes possess to a large extent specifically adjustable characteristics. Inorganic initial substances form a new solid chemical compound with organic initial substances. The inorganic initial component consists of a biocompatible silicate glass and/or a silicate glass ceramic of the system SiO.sub.2 -Al.sub.2 O.sub.3 -MgO-Na.sub.2 O/K.sub.2 O-F.sup.-, and/or a bioactive phosphate silicate glass and/or a phosphate silicate glass ceramic of the system SiO.sub.2 -Al.sub.2 O.sub.3 -MgO-Na.sub.2 O/K.sub.2 O-CaO-P.sub.2 O.sub.5 F.sup.- and/or of the system SiO.sub.2 -MgO-K.sub.2 O-F.sup.- -CaO-P.sub.2 O.sub.5, and/or a bioactive phosphate glass and/or a phosphate glass ceramic of the system P.sub.2 O.sub.5 -Al.sub.2 O.sub.

Abstract: Two parts are used each of which grips a respective, opposite wheel segment, much in the manner of a cowl. Each part includes a straight strip which lies against the outside of the wheel and a shorter straight strip which lies against the inside of the wheel. The adjacent ends of the inner and outer strips are connected by chains or by bands as are intermediate portions of the strips. The two outer strips are releasably connected on the outside of the wheel by diverse types of connections. In some embodiments, each part includes a bow lying against the outside of the wheel and connecting the ends of the outer strip of that part.