The subject of the invention is the flexible roadway support frame to protect dog headings.

The flexible roadway support frame with a roof-bar arch and sidewall arches connected with each other by means of stirrups with overlap where the roof-bar arch has two bending curvature of which one is equal to the mating bending curvature of the sidewall arch, is known from Polish patent description no. 189601.

According to Polish patent description no 192108 there is also the flexible roadway support frame that has a spatial structure with increased own stability, made from brackets lying in different planes and connected with each other by means of a connector in the ceiling part releasably. The brackets lie in three planes and, when viewed from above, form the letter "Y" whose base is a single bracket on one side of the ceiling connector while arms are formed by a doubled bracket on the other side of that connector. The brackets can lie in convergent planes or parallel planes. The doubled bracket can have a sidewall connector. The connectors from double-yoke stirrups whose lower yokes are permanently connected with each other in their side parts by means of metal plates.

As specified in Polish patent description no. 209561 there is also the roadway support frame made from channel sections and protected against damage due to sidewall loads. They have floor supporting elements in the form of portions of channel sections whose upper part is straight and attached from inside to the straight parts of the sidewall arches of the frame while its lower part is curved. Lower parts of the floor supporting elements are finished with supporting plates.

The design of the flexible roadway support frame according to this invention provides for the application of roof-bar arches and sidewall arches with a cut-out at the ends of the arches with a specified size at the distance(a), depth(c) and width(b) as in Fig. 2, in the shape of a rectangular, square or other according to the invention. The cut-out must be such that its lateral planes line in the planes perpendicular to the longitudinal axis of such section.

The cut-out mates the driver of the lower double-yoke stirrup as a result of which it moves along with the arch. Such solution ensures better mating of the arches moving in the joint by eliminating the chance that the stirrup might get jammed, which can result in the screw joint being destroyed. The cut-out in the arches made according to the invention significantly simplifies the making of an upper yoke to the lower double- yoke stirrup and reduces its material consumption. That way we can easily determine the force of destruction of the driver, which is important in emergency situations. The driver in upper yokes allows for operation on both sides, which is currently impossible.

The object of the invention is presented as an exemplary embodiment in figures 1 and 2.

The flexible roadway supporting frame Fig. 1 equipped with roof-bar arches(l) and sidewall arches(2) connected with each other by means of stirrups with overlap(3, 4, 5). The arches have cut-outs on flanges located at the ends of those arches Fig 2.