Unformatted text preview: 4 j j =4 M = 6(n − j − 1) + ∑ fi
S
i =1 C 1 = 6(4 − 4 − 1) + 3 + 2 + 1 + 1 = −6 + 7 = 1 Mobility = 1 Idle DOF = 0 n =4 j j =4 M = 6(n − j − 1) + ∑ fi H 3 4 S 2 C 1 (e)
H i =1 = 6(4 − 4 − 1) + 3 + 2 + 1 + 1 = −6 + 7 = 1 Mobility = 1 Idle DOF = 0  32  H 3 (f) P 4 2 S n =4 j =4 j M = 6(n − j − 1) + ∑ fi
i =1 = 6(4 − 4 − 1) + 3 + 2 + 1 + 1 = −6+ 7 = 1 Mobility = 1 Idle DOF = 0
1 C S 3 C (g) 2 R 1 4 P n =4 j =4 j M = 6(n − j − 1) + ∑ fi
i =1 = 6(4 − 4 − 1) + 3 + 2 + 1 + 1 = −6 + 7 = 1 Mobility = 1 Idle DOF = 0 S 3 C (h) 2 n =4 j =4 j M = 6(n − j − 1) + ∑ fi
i =1 H R
1 4 = 6(4 − 4 − 1) + 3 + 2 + 1 + 1 = −6 + 7 = 1 Mobility = 1 Idle DOF = 0 n =4 j j =4 M = 6(n − j − 1) + ∑ fi
i =1 S
3 C (i) 2 4 R 1 R = 6(4 − 4 − 1) + 3 + 2 + 1 + 1 = −6 + 7 = 1 Mobility = 1 Idle DOF = 0  33  Problem 1.29 Determine the mobility and the number of idle degrees of freedom for each of the mechanisms shown. Show the equations used to determine your answers. For the idle degrees of freedom, identify the input and output links assumed. (a) (b) (c)  34  Problem 1.30 Determine which (if either) of the following linkages can be driven by a constantvelocity motor. For the linkage(s) that can be driven by the motor, indicate the driver link. 4.2" 2.0" 4.0" 2.6" 5.2" (a) (b) 2.7" 2.0" 5.0" (a) 4.2" 2.0" 4.0" 2.6" s + l < p + q Grashof type 1 s = 2.0; l = 4.2; p = 2.6; q = 4.0 2.0 + 4.2 < 2.6 + 4.0 ⇒ 6.2 < 6.6 ⇒ Grashof type 1 The mechanism is a crank rocker if the 2" crank is the driver. (b) 2.0" 5.0" s + l < p + q Grashof type 1 5.2" 2.7" s = 2.0; l = 5.2; p = 2.7; q = 5.0 2.0 + 5.2 < 2.7 + 5.0 ⇒ 7.2 < 7.7 ⇒ Grashof type 1 The mechanism is a crank rocker if the 2" crank is the driver.  35  Problem 1.31 Assume that you have a set of links of the following lengths: 2 in, 4 in, 5 in, 6 in, 9 in. Design a 4bar linkage that can be driven with a continuously rotating electric motor. Justify your answer with appropriate equations, and make a scaled drawing of the linkage. Label the crank, frame, coupler, and rocker (follower). Coupler 5.0" 4.0" Rocker 2.0" Crank 6.0" Frame s +l < P + q ⇒ Grashof type 1 6 + 2 <5 + 4 ⇒ 8 <9 Therefore the linkage is a type 1 linkage and a crank rocker Problem 1.32 Assume that you have a set of links of the following lengths: 20 mm, 30 mm, 45 mm, 56 mm, 73 mm. Design a fourbar linkage that can be driven with a continuousrotation electric motor. Justify your answer with appropriate equations, and make a freehand sketch (labeled) of the resulting linkage. Label the crank, frame, coupler, and rocker (follower). Coupler 56 mm 45 mm Rocker 20 mm Crank 73 mm Frame s + l < p + q ⇒ Grashof type 1 linkage 20 + 73 < 45 + 56 ⇒ 93 < 101  36  Problem 1.33 For the fourbar linkages below, indicate whether they are Grashof type 1 or 2 an...
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This note was uploaded on 02/20/2011 for the course MEC 411 taught by Professor Shudong during the Winter '11 term at Ryerson.
 Winter '11
 Shudong

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