A deceleration device adapted for gradual dissipation of kinetic energy comprises a spool reel carrying a belt being wound up on the spool reel; an elevating spindle being driven by the spool reel when the belt is being retracted from the spool reel; at least one collet screwed to the elevating spindle; and at least one spring assembly being installed between the collet and a fixed bearing portion of the deceleration device. The at least one collet is screwed towards the fixed bearing portion by retraction of the belt from the spool reel thereby compressing the spring assembly, whereby a reaction load is generated by the spring assembly counteracting the retraction of the belt.