MD - BELTS, SPROCKETS, BOLTS AND SCREW Flashcards
Find the horsepower required to drive a power screw lifting a load of
4000 Ibs. A 2 and 1/2 inches double square thread with two threads/in. is to be used. The frictional radius of the collar is 2 inches and the coefficients of friction are 0.1 for the threads and 0.15 for the collar.
The velocity of the nut is 10 ft/min.
A. 5.382 HP
C. 3.683 HP
B. 4.395 HP
D. 6.472 HP
B. 4.395 HP
A single square thread power screw is to raise a load of 70 KN. The screw has a major diameter of 36 mm and a pitch of 6 mm. The coefficient of thread friction and collar friction are 0.13 and 0.10 respectively. If the collar mean diameter is 90 mm and the screw turns at 60 rpm, find the combined efficiency of screw and collar,
A. 13.438%
C. 14.526%
B.15.530%
D. 12.526%
D. 12.526%
Determine the diameter of the stud bolt that are required to fasten down the cylinder head of a 203 mm x 304 mm gas engine. There are ten bolts on the block. The explosion pressure is 31 kg/sq cm and studs are made of ordinary bolts material SAE 1020. How deep should the bolt be drilled?
* 38.1 mm
* 40.2 mm
* 37.3 mm
* 35.5 mm
- 38.1 mm
A single-threaded trapezoidal metric thread has a pitch of 4 mm and a mean diameter of 18 mm. It is used as a translation screw in conjunction with a collar having an outside diameter of 37 mm and an inside diameter of 27 mm. Find the required torque in N-m to raise a load of 400 kg if the coefficient of friction is 0.3 for both thread and collar.
A.34.6 N-m
B.32.6 N-m
C.39.1 N-m
D.38.5 N-m
B.32.6 N-m
A safety valve spring having 9 and 1/2 coils has the ends squared and ground. The outside diameter of the coil is 115 mm and the wire is 13 mm. It has a free length of 203 mm. Determine the length of the wire to which this spring must be initially compressed to hold a boller pressure of 1.38 Ma on the valve seat of 32 mm diameter. Modulus ofrigidity is taken as G = 80 GN/m?.
A. 172 mm
C. 192 mm
B. 179 mm
D. 158 mm
A. 172 mm
An ammonia compressor is driven by a 20 kW motor. The compressor and the motor RPM are 360 and 1750, respectively. The small sheave has a pitch diameter of 152.4 mm. If the belt to be used is standard C-120 (L=122.9 in.), determine the center distance between sheaves A.709 mm
C. 806 mm
B. 865 mm
D. 686 mm
C. 806 mm
An air compressor is driven by a 7.5 HP electric motor with a speed of1750 rpm with standard A-60 V- belts of length 61.3 in. The pitch diameter of the small sheave is 110 mm and the larger sheave is 200 mm. Service factor is 1.2. Determine the arc of contact.
173.92 degrees
183.56 degrees
169.87 degrees
212.65 degrees
169.87 degrees
A pulley 610 mm in diameter transmits 40 kW at 500 RPM. The arc of contact between the belt and pulley is0.35 and the safe working stress in Newton
of the belt is 2.1 MPa. Find the tangential force at the rim of the pulley
2,406 N
B. 4,321 N
* 2,505 N
* 3.321 N
2,505 N
A pulley 610 mm in diameter transmits 40 kW at 500 RPM. The arc of contact between the belt and pulley is 144 degrees, the coefficient of friction between belt and pulley is 0.35 and the safe working stress of the belt is 2.1 and the safe working stress of the belt is 2.1 MPa. What Is the effective belt pull in Newton A.
2,505 N
B. 3,931 N
* 4,528 N
* 2,823 N
2505 N
A certain farm equipment which requires 2200 Newton mater torque at
500 RPM has a diesel engine to operate at 1500 RPM as its prime mover. A No. 60 roller chain with a total length of 60 pitches and a small sprocket with 23 teeth are to be used with an operating temperature to remain constant at 45 degree C. Determine the no. of teeth of the larger sprocket.
A.70
B.79
C. 68
D. 69
D. 69
A 4 inches diameter shaft is driven at 3600 pm by a 400 Hip motor. The shaft drives a 48 inches diameter chain sprocket having an output efficiency of 85%. The output force of the driving sprocket and the output of the driven sprocket are:
* 200 lb and 250 hp
* 261.8 lb and 300 hp
* 291.66 lb and 340 hp
* none of the above
291.66 lb and 340 hp
A cylinder head of a steam engine is held on by 16 bolts. The effective diameter of the cylinder is 40 cm and the steam pressure is 9 kg/cm?.
Assuming that the bolts are not initially stressed, find the diameter of each of the bolts if the tensile stress is not to exceed 250 kg/cm?.
A. 18.97 mm
C. 97.18 mm
B. 81.97 mm
D. 81.79 mm
A. 18.97 mm
An eyebolt is lifting a block weighing 580 lbs. The eyebolt is of SAE C1040 material with Su=68 ki and Sy=65 ki, what is the stress area (in inches square of the bolt if it is under the unified coarse series thread?
A. 0.1271 in?
C. 0.1371 in?
B. 0.1471 in?
D. 0.1571 in?
B. 0.1471 in?
Compute the diameter of a set screw required to transmit 8 HP at a shaft speed of 850 rpm. The shaft diameter is 2-in.
A. 0.4331 in
C. 0.5113 in
B. 0.5331 in
D. 0.4332 in
What is the friction horsepower acting on a collar loaded with 600 kg weight? The collar has an outside radius of 110 mm and 80 mm inside is 160 rpm.radius. The coefficient of friction of the collar is 0.2. Assume the speec
* 3.5 hp
* 4.5 hp
* 1.5 hp
* 2.5 hp
- 3.5 hp
What is the working stress of a 40 mm diameter bolt which is screwec up tightly in a packed joint when the working strength is 12 tons?
* 32358 psi
* 35328 psi
* 32258 psi
* 52328 psi
- 32358 psi
A triple thread screw has a lead of 25 mm. Find the number of thread per inch.
A.B.0.348 thread per inch
C.3.048 thread per inch
B.0.483 thread per inch
D. 3.480 thread per inch
C.3.048 thread per inch
A square thread screw has an efficiency of 70% when friction of thread is 0.10 and collar friction is negligible. Find the lead angle, in deg.
A. 14.3 deg
C. 15.3 deg
B. 16.3 deg
D. 12.3 deg
A. 14.3 deg
A square thread power screw has a pitch diameter of 1.8 and lead of 1-in. Neglecting collar friction, compute the coefficient of friction for the threads if the screw efficiency is 65%.
A. 0.90803
C. 0.80903
B.0.09083
D. 0.30980
B.0.09083
A cylinder head of a steam engine is held on by 16 bolts. The effective diameter of the cylinder is 40 cm and the steam pressure is 9 ka/cm.
Assuming that the bolts are not initially stressed, find the diameter of each of the bolts if the tensile stress is not to exceed 250 kg/cm?.
A. 19.87 mm
C. 17.98 mm
B. 18.97 mm
D. 17.87 mm
B. 18.97 mm
An eyebolt is lifting a block weighing 580 lbs. The eyebolt is of SAE (1040 material with Su=68 ki and Sy=65 ksl, what is the stress area (ir inches square) of the bolt if it is under the unified coarse series thread?
* 0.1271 in?
C. 0.1371 in?
* 0.1471 in?
D. 0.1571 in?
- 0.1471 in?
Compute the diameter of a set screw required to transmit 8 HP at shaft speed of 850 pm. The shaft diameter is 2-In.
A. 0.3315 in
C. 0.1335 in
B. 0.1553 in
D. 0.5331 in
D. 0.5331 in
What is the friction horsepower acting on a collar loaded with 600 kg weight? The collar has an outside radius of 110 mm and 80 mm inside radius. The coefficient of friction of the collar is 0.2. Assume the speec is 160 rpm.
A. 5.2 hp
B. 2.3 hp
2.4 hp
2.5 hp
0.198 HP
What is the working stress of a 40 mm diameter bolt which is screwed up tightly in a packed joint when the working strength is 12 tons?
A. 22538 psi
C. 32258 psi
B.22853 psi
D. 58223 ps
32258 psi