Patent ID: 7798288

Claim:
In combination, a ladder, a vertical ladder, or a vertical iron gangway and a climbing aid for the ladder, the vertical ladder or the vertical iron gangway, the combination comprising: an upper guide pulley; a lower guide pulley, wherein one of the guide pulleys is a drive disc; an endless traction means running between the upper guide pulley and the lower guide pulley from which a person can hang by a suspension device; a drive device including a drive motor which drives the drive disc which drives the traction means; a drive force limitation device including a slip clutch with torque limitation interposed between the drive disc and the drive motor; and a device for switching the drive device on and off which is actuated by means of the endless traction means, wherein the device for switching the drive device on and off includes a sensor with which movement of the traction means can be detected and a pulse generation element which is directly connected to the drive disc, whereby the sensor further includes a pulse detector which senses a sensor pulse from the pulse generation element that switches the drive motor on, and an absence of detecting a subsequent sensor pulse within a time span switches the drive motor off.