A measurable, and perhaps a quite substantial, force is required to move the levers connecting the back roller to the regulating device, against frictional resistance in their bearings and at their points of contact.

• 需要一个可测量的而且是非常重要的力来克服轴承和联接处的摩擦阻力,以便驱动联接后梁和调节装置的连杆。