The mechanism of Prob. 4/141 is repeated here. The torsional spring at B is undeformed when bars OB and BD are both in the vertical position and overlap. If a force F is required to position the bars at a steady orientation ? = 60?, determine the torsional spring stiffness kT. The slot at C is smooth, and the weight of the bars is negligible. In this configuration, the pin at C is positioned at the midpoint of the slotted bar.

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Problem. 4/141??

The torsional spring at B is undeformed when bars OB and BD are both in the vertical position and overlap. If a force F is required to position the bars at a steady orientation ? = 60?, determine the torsional spring stiffness kT. The slot at C is smooth, and the weight of the bars is negligible. In this configuration, the pin at C is positioned at the midpoint of the slotted bar.

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.0| 8 to|O B, KT D F OE .o |~ B kt D