THE INVENTION RELATES TO AN ADDITIONAL ROLLER HAVING A RIGID FRAME (3), WITH A DRIVABLE WHEEL (2) WHICH IS MOUNTED IN THE FRAME (3) AND HAS A SHAFT (7), WHEREIN THE WHEEL (2) TOGETHER WITH THE FRAME (3) CAN BE RAISED OR LOWERED BY PIVOTING RELATIVE TO A CHASSIS, ON WHICH THE ADDITIONAL ROLLER IS TO BE MOUNTED, AND A COMPRESSION SPRING (13) WHICH IS COUPLED ROTATABLY AT ONE END TO THE CHASSIS IS PROVIDED, IN ORDER, IN THE LOWERED POSITION, TO LOAD THE WHEEL (2) IN RESPECT OF GROUND CONTACT. IN ORDER TO PROVIDE A SIMPLE AND EFFECTIVE ARRANGEMENT OF THE COMPRESSION SPRING WITH REGARD TO THE WHEEL AND THE FRAME ACCOMMODATING THE WHEEL, IT IS PROPOSED THAT A TRANSVERSE CONNECTION (6) CONNECTING TWO FRAME PARTS (4, 5) IN THE DIRECTION OF A SHAFT (7) OF THE WHEEL (2) IS PROVIDED, THAT THE COMPRESSION SPRING (13) IS COUPLED AT THE OTHER END TO THE TRANSVERSE CONNECTION (6), AND THAT THE COMPRESSION SPRING (13) TOGETHER WITH THE FRAME (3) PIVOTS ABOUT THE CHASSIS-MOUNTED PIVOT POINT DURING RAISING AND LOWERING OF THE WHEEL (2). FIGURE 1
