1) A cam with a minimum radius of 25 mm, rotating clockwise at a uniform speed is to be designed to give a roller follower at the end of a valve rod. The motion of the follower is described below:
a) To rise the valve through 40 mm during 90°of rotation of cam,
b) To keep the valve fully raised through next 60°;
c) To lower the valve during next 90° and
d) To keep the valve closed during the rest of the revolution.
The diameter of the roller is 25 mm. the displacement of the valve, while being raised and lowered is to take place with SHM. Sketch the cam profile such that the line of stroke of the valve rod passes through the axis of the cam shaft.
2) Two gear wheels mesh externally and are to give a velocity ratio 3:1; the teeth are involutes form and module is 6 mm. Assume addendum is equals to one module, pressure angle is 20°, pinion rotates at 90 rpm. Compute:
a) No. of teeth on the pinion to avoid interference on it and the corresponding number of teeth on the wheel.
b) The length of path and arc of contact
c) The No. of pairs of teeth in contact
d) Maximum velocity of sliding.
3) In a reverted epicyclic gear train, the arm A carries two gears B, C and a compound gear D-E. The gear B meshes with gear E and gear C meshes with gear D. the number of teeth on gears B, C and D are 75, 30, and 90 respectively. Find the speed and direction of gear C when the gear B is fixed and the arm A makes 100 rpm Clockwise.
4) A Proell governor has equal arms of length 300 mm. the upper and lower ends of the arms are pivoted on the axis of the governor. The extension arms of the lower links each 80 mm long and parallel to the axis when the radii of rotation of the balls are 150 mm and 200 mm. the mass of each ball is 10 kg and the mass of the central load is 100 kg. Compute the range of speed of the Governor.
5) A porter governor has all four arms 300 mm long. The upper arms are attached on the axis of rotation and the lower arms are attached to the sleeve at a distance of 25 mm from the axis. The mass of each ball is 8 kg and the sleeve has a mass of 60 kg. The extreme radii of rotation are 200 mm and 250 mm. determine the range of the speed of the governor.