This patient had a recurvatum problem at the knee; so, the posterior shell might have been given to this patient to gain some time until the patient's knee flexors became stronger.
Apply torque to a bolt head only when a torque wrench cannot be used on the nut. After application of torque to a nut, further tightening to align the slot for cotter pin or lockwire is permitted. a. Torque Definitions. Torque definitions are explained In the following paragraphs. (1) Breakaway torque Breakaway torque (table 2-8) is defined as minimum torque required to start the movement of a nut on or off bolt with no axial load on the nut and with the bolt completely through the nut. (2) Friction torque (tare, drag, run on).
Preload is the tension created in a fastener when it is tightened. This tensile force in the bolt creates a compressive force in the bolted joint known as clamp force. For practical purposes, the clamp force in an unloaded bolted joint is assumed to be equal and opposite of the preload.ither is acceptable, however a torque value defined for tightening the head does not necessarily apply to tightening the nut. Tightening the head vs. the nut can result in different nut factors and therefore change the torque required to achieve proper preload.