Lifting is done using the two springs, each of which is attached to the anchor bracket at A and to the counterbalance shaft at B and C. As the door is raised, the springs begin to unwind from the shaft, thereby assisting the lift. If each spring provides a torsional moment of M = (0.7θ) N·m, where θ is in radians, determine the angle θ0 at which both the left-wound and right-wound spring should be attached so that the door is completely balanced by the springs, i.e , when the door is in the vertical position and is given a slight force upward, the springs will lift the door along the side tracks to the horizontal plane with no final angular velocity. Note: The elastic potential energy of a torsional spring is
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Engineering Mechanics: Dynamics (14th Edition)
- The control lever is subjected to a clockwise couple of 81 N·m exerted by its shaft at A and is designed to operate with a 230-N pull as shown. If the resultant of the couple and the force passes through A, determine the proper dimension x of the lever.Assume F = 230 N, a = 165 mm, θ= 22°.arrow_forwardThe device shown is a part of an automobile seat- back-release mechanism. The part is subjected to the 4-N force exerted at A and a 300-N mm restor- ing moment exerted by a hidden torsional spring. Determine the y-intercept of the line of action of the single equivalent force. F=4N 10 mm 15° 40 mm 300 N mm SHOT ON POCO X3 NFCarrow_forwardExample The device shown is a part of an automobile seat- back-release mechanism. The part is subjected to the 4-N force exerted at A and a 300-N mm restor- ing moment exerted by a hidden torsional spring. Determine the y-intercept of the line of action of the single equivalent force. F=4N 10 mm 15° A 40 mm 3. 300 N-mmarrow_forward
- The friction at sleeve A can provide a maximum resisting moment of 380 Nm about the x-axis. Determine the largest magnitude of force F that can be applied to the bracket so that the bracket will not rotate about the x-axis. Given that L1 is 275 mm, L2 is 171 mm and L3 is 126 mm. Z F 60° X L1 mm A B 45° 60° L3 mm L2 mm yarrow_forwardThe throttle-control sector pivots freely at O. If an internal torsional spring exerts a return moment M = 3.5 N·m on the sector when in the position shown, for design purposes determine the necessary throttle-cable tension T so that the net moment about O is zero. Note that when T is zero, the sector rests against the idle-control adjustment screw at R.arrow_forward2/37 A 150-N pull T is applied to a cord, which is wound securely around the inner hub of the drum. Determine the moment of T about the drum center C. At what angle e should T be applied so that the moment about the contact point P is zero? T- 150 N 125 mmy 200mm PROBLEM 2/37arrow_forward
- The ideal spring of constant k=2.6kN/m is attached to the fitted at point A and the end fitted at point B, as shown. The spring is unstretched when theta(A) and theta(B) are both zero. If the fitted is rotated 15⁰ clockwise and the end fitting is rotated 30⁰ counterclockwise, determine the vector expression for the spring force F. Determine distance C so that the moment the spring force makes about the Z axis is equal to 10.82 N.marrow_forward2/37 A 150-N pull T is applied to a cord, which is wound securely around the inner hub of the drum. Determine the moment of T about the drum center C. At what angle should T be applied so that the moment about the contact point P is zero? T- 150 N 125 mmy cf 200mm PROBLEM 2/37arrow_forwardThe throttle-control lever OA rotates in the range 0 ≤ 0 ≤ 90°. An internal torsional return spring exerts a restoring moment about O given by M = K(0+π/4), where K = 550 N-mm/rad and is in radians. Determine and plot as a function of the tension T required to make the net moment about O zero. The effects of the radius of the pulley at B are negligible. After you have completed the plot, answer the questions. Assume r = 45 mm, d = 90 mm. B 45° d M Answers: If 0 = 31°, the tension T = If 0 = 41°, the tension T = If 0 = 62°, the tension T = i i i T N N Z Z Narrow_forward
- Determine the moment Mox produced by the force F = 50 lb which tends to rotate the rod about the x axisarrow_forwardThe throttle-control lever OA rotates in the range 0 ≤ 0 ≤ 90°. An internal torsional return spring exerts a restoring moment about O given by M = K(0+π/4), where K = 680 N.mm/rad and is in radians. Determine and plot as a function of the tension T required to make the net moment about O zero. The effects of the radius of the pulley at B are negligible. After you have completed the plot, answer the questions. Assume r = 55 mm, d = 120 mm. 45° T Answers: If 0 = 22°, the tension T = i If 0 = 47°, the tension T = i If 0 = 74°, the tension T = i N N Narrow_forwardThe 30-N force Pis applied perpendicularly to the portion BC of the bent bar Determine the moments of P about point 8 and about point 4. P= 30N 16 m 45 16 m definedarrow_forward
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