A patient transport device for transporting a patient in a vehicle, comprising - an undercarriage with swivel castors and/or rollers, an upper frame and, possibly, a lower frame, and with a lifting means adapted to be automatically operated using a drive, - the height position of the upper frame being variable, in particular in a continuous manner, between a lowest lifting position and a highest lifting position, using the lifting means, and - a lying surface, which has a head-side end and a foot-side end, at and/or on the upper frame, which is connected to the upper frame or is detachably connectable to the upper frame, - the lying surface comprising a middle part with a first end facing the head-side end of the lying surface and a second end facing the foot-side end of the lying surface, a backrest part articulately connected to the first end of the middle part and pivotable about a first pivot axis which extends transversely to the longitudinal extension of the lying surface defined by the head-side end and the foot-side end of the lying surface, and a lower leg/foot part arranged to be pivotable relative to the middle part about a second pivot axis parallel to the first pivot axis, which lower leg/foot part is adapted, with the backrest part pivoted upward, to be folded down to form a patient chair, characterized by - a safety means arranged at the lower leg/foot part for preventing damage to the lying surface, in particular the lower leg/foot part of the lying surface and/or the undercarriage and/or an injury to a person while lowering the undercarriage in the folded-down state of the lower leg/foot part, - the safety means comprising a touch sensor arranged at the foot-side end of the lower leg/foot part, which sensor outputs an output signal to automatically switch off the lifting device upon contact of the lower leg/foot part with the lower carriage or with a substrate on which the undercarriage rests or with a body on the substrate, e.g. a person's foot. - an undercarriage with swivel castors and/or rollers, an upper frame and, possibly, a lower frame, and with a lifting means adapted to be automatically operated using a drive, - the height position of the upper frame being variable, in particular in a continuous manner, between a lowest lifting position and a highest lifting position, using the lifting means, and - a lying surface, which has a head-side end and a foot-side end, at and/or on the upper frame, which is connected to the upper frame or is detachably connectable to the upper frame, - the lying surface comprising a middle part with a first end facing the head-side end of the lying surface and a second end facing the foot-side end of the lying surface, a backrest part articulately connected to the first end of the middle part and pivotable about a first pivot axis which extends transversely to the longitudinal extension of the lying surface defined by the head-side end and the foot-side end of the lying surface, and a lower leg/foot part arranged to be pivotable relative to the middle part about a second pivot axis parallel to the first pivot axis, which lower leg/foot part is adapted, with the backrest part pivoted upward, to be folded down to form a patient chair, - a safety means arranged at the lower leg/foot part for preventing damage to the lying surface, in particular the lower leg/foot part of the lying surface and/or the undercarriage and/or an injury to a person while lowering the undercarriage in the folded-down state of the lower leg/foot part, - the safety means comprising a touch sensor arranged at the foot-side end of the lower leg/foot part, which sensor outputs an output signal to automatically switch off the lifting device upon contact of the lower leg/foot part with the lower carriage or with a substrate on which the undercarriage rests or with a body on the substrate, e.g. a person's foot.