The steps of a conventional escalator are fastened to two transport chains and form together therewith an endless, circulating step belt which runs over a respective pair of transport chainwheels at each of the two ends of the escalator, wherein one transport chainwheel pair belongs to a drive station and drives and deflects the step belt, and the other chainwheel pair is part of a step belt deflecting station. The individual steps of the step belt are each equipped with two front and two rear guide rollers, through which the steps are guided in a position-dependent orientation by guidance and deflection curves primarily fastened to the support construction of the escalator.
The steps of the escalator run along a predetermined path laterally defined by a stationary base plate. A passenger located on the tread surface of a trailing step stands opposite the riser surface of a leading step. In the outlet region the trailing step slides along the riser surface of the leading step, so that the riser surfaces of the leading and trailing steps come onto the same plane. Ribs are between two steps in order to minimise the contact area between the steps and a standing object. However, notwithstanding all this there is a gap between the ribs of two adjacent steps.
In order to provide compensation for tolerances a gap must remain between a leading step and a trailing step, since two steps bearing against one another would produce substantial friction which would lead to unacceptable heating and increase drive power as well as wear. For this reason a space or air gap must be left between leading and trailing steps.
A space or a gap of that kind is a safety risk. Due to the play which is present, the gap width can widen so that engagement therein of a shoe edge, heel, skirt hem or hand, particularly with children, is possible. As a consequence thereof the risk of squashing and other injuries for the passenger is present.
The injury of persons in the riser region caused by the relative movement between the moving steps is a principal problem of conventional escalators. Beyond that, if an object located on a moving step comes into contact with the opposite riser surface, the object can be drawn into the gap by friction and the simultaneous relative movement of the leading and trailing steps, particularly in the case of upward escalator travel.
Patent JP 11171462 discloses brushes which are arranged on a trailing step in order to clean the riser surface of the leading step. The brushes are disposed at a certain spacing below the tread surface, so that objects can jam in the gap disposed thereabove. Moreover, the brushes are in contact with the riser, can damage the riser and cause noise. In addition, such a construction has proved disadvantageous that the brushes, due to the constant friction with the riser, have only a very short service life. The forces exerted by the steps damage the structure of the brushes, which then have insufficient shape stability.
It is accordingly an object of the present invention to provide an escalator which does not have the above-mentioned disadvantages and which substantially increases operational reliability in conjunction with ease of manufacture and significantly extends service life.