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Published byEmmeline Lamb Modified over 5 years ago
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4-2 Determine the type of the linkage and the type of the two side links AB and DC (crank or rocker) according to the Grashof criterion. Can the coupler BC rotate 360o with respect to the frame (Yes or No)?
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4-4 In the revolute four-bar mechanism similar to the one in Fig
4-4 In the revolute four-bar mechanism similar to the one in Fig.4-23(b), let LAB=60mm, LBC =130mm, LDC=140mm, LAD=200mm, and BAD=135o. (1) Determine the type of the revolute four-bar mechanism. Crank-Rocker
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4-4(2) If the side link AB is a driver and rotates at a constant speed, (a) find the pressure angle and the transmission angle of the mechanism at that position.
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(b) find the angular stroke max of the link DC
(b) find the angular stroke max of the link DC. (c) find the crank acute angle between the two limiting positions. (d) calculate the time ratio k .
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(e) will any dead-point occur during the whole cycle of the motion. No
(e) will any dead-point occur during the whole cycle of the motion? No. (d) find the maximum pressure angle max and the minimum transmission angle min. min =min{min, min} 不能只求min !!!
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(3) If the side link DC is a driver, (a) find the pressure angle ’ and the transmission angle ’ of the mechanism at that position.
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(b) will any dead-point occur during the whole cycle of the motion
(b) will any dead-point occur during the whole cycle of the motion? If so, when? Yes. (c) find the maximum pressure angle max and the minimum transmission angle min.
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若DC为原动件,图示两位置的不是min!!
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4-5 In the offset slider-crank mechanism shown in Fig
4-5 In the offset slider-crank mechanism shown in Fig.4-5, the driver crank AB rotates at a constant speed. Let LAB=120mm, LBC=250mm, offset e=60mm, and AB=60o. Find
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(1)the length of stroke H of the slider, (2) the crank acute angle (3) the time ratio k ,
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(4) and at that position, (5) max and min.
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4-3 In a revolute four-bar linkage ABCD, LBC=100mm, LDC =80mm, LAD=110mm. (1)Find the range of the values for the length LAB of link AB if the linkage is either (a) a crank-rocker mechanism with crank AB, or (b) a double-rocker mechanism. (2) Can the linkage be a double-crank mechanism by choosing LAB suitably? Why?
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4-7 In the double-crank linkage ABCD shown in Fig
4-7 In the double-crank linkage ABCD shown in Fig.4-1(b), LAB=80mm, LBC=180mm, LDC=230mm, LAD=200mm. The driver BC rotates at a constant speed. Find the minimum transmission angle min of the linkage.
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4-8 According to the data in Problem 4-3, find the range of values for the driving crank AB if the linkage is to be a crank-rocker mechanism and the minimum transmission angle min is larger than 50o. Compare the result with that in Problem 4-3(1a).
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4-9 The crank-rocker mechanism shown in Fig
4-9 The crank-rocker mechanism shown in Fig.4-31 has no quick-return characteristics. Prove that the lengths of links of the linkage satisfy the following equation: (LAB)2 + (LAD)2 =(LBC)2 + (LDC)2
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