Whitworth quick-return motion mechanism:

Configuration diagram of a Whitworth quick-return motion mechanism is illustrated in given figure. Conclude velocity of slider D in terms of angular velocity of crank O₂A (ω₂). The centre distance among the fixed axes of crank shaft & the slotted lever is 130 mm. 550 mm is the length of the slotted lever AC along its position from the axis of rotation of the lever to point C start 150 mm. Links 2 & 5 are respectively 280 mm and 720 mm.

Solution

No. of links = 6

∴          No. of I.Cs = (6 × 5)/2 = 15

Out of these, seven may easily be identified and they are following

O₂ → I₁₂, O₄ → I₁₄, A = I ₂₃, C → I ₄₅ and D → I₅₆

 I₁₆ is at infinity on a line vertical to the motion of slider D. I₃₄ is also at infinity on a line vertical to the link 4.

To determine velocity of slider D, you have to find I₂₆ that has been illustrated by thick line in circle diagram in given figure. To determine I₂₆, you must first determine I₂₅ or I₃₆. Now I₂₄ & I₁₅ can be resolute as these are represented through the common sides of triangles 2, 3, 4 & 1, 2, 4 and triangles 1, 4, 5 & 1, 6, 5, respectively. I₂₅ may then be resolute from triangles 1, 2, 5 & 2, 4, 5 with 2-5 as common side. I₂₆ may be determined from triangles 2, 5, 6 & 1, 2, 6 along 2-6 as common side.

            Table of I. Cs

I₁₂         I₁₃         I₁₄         I₁₅         I₁₆

            I₂₃         I₂₄         I₂₅         I₂₆

                        I₃₄         I₃₅         I₃₆

                                    I₄₅         I₄₆

                                    I₅₅         I₅₆

  Whitworth Quick-return Motion Mechanism

The velocity of slider D, V_D = ω₂ × O₂ I₂₆ with direction perpendicular to line O₂ I₂₆. (Calculate yourself).