1. Repeat problem 12-7 if everything remains the same except that the power screw has double square threads. 2.A 40-mm rotating power screw with triple square threads has a pitch of . The screw is to be used to lift a 22 kN load at a speed of 4 m/min. Friction coefficients for both the…

1. A 20-mm power screw for a hand-cranked arbor press is to have a single-start square thread with a pitch of 4 mm. The screw is to be subjected to an axial load of 5 kN. The coefficient of friction for both threads and collar is estimated to be about 0.09. The mean friction diameter…

1.You have been assigned the task of examining a number of large flood gates installed in 1931 for irrigation control at a remote site on the Indus River in Pakistan. Several large steel bolts appear to have developed cracks, and you have decided that they should be replaced to avert a potentially serious failure of…

1.A high-speed “closing machine” is used in a tomato canning factory to install lids and seal the cans. It is in the middle of the “pack” season and a special bracket has separated from the main frame of the closing machine because the -24 UNF-2A hex-head cap screws used to hold the bracket in place…

1.A standard coarse-thread metric cap screw made of steel has a major diameter of 10.0 mm. If a torque wrench is used to tighten the cap screw to a torque of 35 N-m, estimate the axial preload force induced in the cap screw. It may be assumed that the coefficient of friction is about 0.15…

1.A -20 UNF-2A SAE Grade 2 steel cap screw is being considered for use in attaching a cylinder head to an engine block made of 356.0 cast aluminum . It is being proposed to engage the cap screw into an internally threaded hole tapped directly into the aluminum block. Estimate the required length of thread…

1. You are asked, as a consultant, to determine a procedure for finding a “best estimate” for the design stress to be used in designing the helical-coil springs for a new off-the-road vehicle. The only known information is: ( 1. ) The spring material is a ductile high-strength ferrous alloy with known ultimate strength, ,…

1. A proposed helical-coil compression spring is to be wound from standard unpeened music wire of 0.038-inch diameter, into a spring with outer coil diameter of inch and12 total turns from end-of-wire to end-of-wire. The ends are to be closed. Do the following: a. Estimate torsional yield strength of the music wire. b. Determine the…

1.A helical-coil compression spring is to be designed for a special application in which the spring is to be initially assembled in the mechanism with a preload of 10 N, and exert a force of 50 N when it is compressed an additional 140 mm. Tentatively, it has been decided to use music wire, to…

1. Two steel, helical-coil compression springs are to be nested around a common axial centerline. The outer spring is to have an inside diameter of 38 mm, a standard wire diameter of 2.8 mm, and 10 active coils. The inner spring is to have an outside diameter of 32 mm, a standard wire diameter of…