In the revolute four-bar mechanism shown below, let L AB =60mm, L BC =130mm, L DC =140mm, L AD =200mm, and Ð BAD=135 o . (1) Determine the type of the revolute four-bar mechanism. (2) If the side link AB is a driver and rotates at a constant speed: (a) find the pressure angle a and the transmission angle g of the mechanism at that position. (b) find the angular stroke y max of the link DC. (c) find the crank acute angle q between the two limiting positions. (d) calculate the time ratio k . (e) will any dead-point occur during the whole cycle of the motion? (f) find the maximum pressure angle a max and the minimum transmission angle g min . (3) If the side link DC is a driver, (a) find the pressure angle a ’ and the transmission angle g ’ of the mechanism at that position. (b) will any dead-point occur during the whole cycle of the motion? If so, when? (c) find the maximum pressure angle a max and the minimum transmission angle g min . 2、 试设计一个铰链四杆机构 ABCD ,已知连杆 BC 长度 l BC =40mm ,它的两个位置如图 所示。现要求以杆 CD 为主动件时,机构的第二个位置为死点位置,且此时 C 2 D 位于 B 1 C 1 的垂直方向上;并求构件长度 l AB 、 l CD 和 l AD 。 3、 设计一曲柄滑块机构,已知滑块的行程 s =60mm ,偏距 e =20mm ,行程速比系数 K =1.25 。试用图解法求: ( 1 )曲柄 AB 的长度 l AB 和连杆 BC 的长度 l BC ; ( 2 )若滑块由左向右运动为工作行程,要使机构具有急特性,曲柄应沿什么方向转动? ( 3 )以曲柄为件时,在图中标出 g min ; ( 4 ) 以滑块为件时,机构有无死点位置?若有,在图中指出。