Influence of Chuck Design on Spin-Out Torque in Softwood Veneer Peeling Blocks

摘要

A substantial test program was conducted to compare the maximum torque deliverable by four different chucks in Douglas-fir, southern pine, white fir, and western hemlock. A fifth chuck was tested in Douglas-fir and southern pine to determine the effects of spur penetration and block temperature on spin-out torque. Based on the results of these tests, some criteria for rational chuck design have been established. Chucks was relatively slender spurs can transmit greater torque before spinning out than can chucks with spurs with relatively large circumferential surface profiles. Maximum torque generally increases with depth of penetration. Therefore, chucks with relatively long, slender spurs are most effective at transmitting torque. The limiting factors are pur strength and stiffness. While slender spurs are desirable they must have sufficient strength to transmit the maximum torque without failure. The yield strength of the spurs must be high enough to prevent permanent deformation of the spurs to occur. At the same time, however, the material must be sufficiently ductile to allow load sharing among the spurs.