Concept explainers
The figure shows a band brake designed to prevent “backward” rotation of the shaft. The angle of wrap is 270°, the band width is
(a) What dimension c1 will just prevent backward motion?
(b) If the rocker was designed with c1 = 1 in, what is the maximum pressure between the band and drum at 150 lbf · ft back torque?
(c) If the back-torque demand is 100 lbf · in, what is the largest pressure between the band and drum?
Want to see the full answer?
Check out a sample textbook solutionChapter 16 Solutions
Shigley's Mechanical Engineering Design (McGraw-Hill Series in Mechanical Engineering)
- A differential band brake is shown in the figure. The diameter of the drum is 800 mm. The coefficient of friction between the band and the drum is 0.3 and the angle of embrace is 240°. When a force of 777 N is applied at the free end of the lever, find: a. The maximum force, in Newtons, in the band for the clockwise rotation of the drum b. The minimum force, in Newtons, in the band for the clockwise rotation of the drum c. The maximum force, in Newtons, in the band for the counter clockwise rotation of the drum d. The minimum force, in Newtons, in the band for the counter clockwise rotation of the drum e. The torque which can be applied by the brake, in N-m, for the clockwise rotation of the drum.arrow_forwardA block brake with a torque of 250 N-m. Its drum rotates at 100 rpm. The length of the block (1) is twice its width (w). Assume, the coefficient of friction P is 0.35. Calculate: (1) the applied load (P) and the hinge-pin reaction (Rx ana Ry) for clockwise rotation of the drum; (2) the applied load and hinge-pin reaction for anticlockwise rotation of the drum; (3) the rate of heat generated during the braking action. (4) The dimensions of the block, if the intensity of pressure between the block and brake drum is 1 MPa. (5) Check whether the brake is self-locking.arrow_forward6. Design a clamp coupling for transmitting 36 kW, at 200 rpm. Allowable shear stress in shaft is 45 MPa, allowable shear stress in key is 40 MPa, and allowable crushing stress in key is 90 MPa. The number of bolts joining the two halves is 4. The permissible tensile stress in bolts is 60 MPa. The coefficient of friction between the muff and shaft can be taken as 0.25arrow_forward
- The following figure shows a belt brake system operating on a brake drum of the hoisting mechanism. It consists of a cylinder with a diameter of 325 mm, the end of which is the elastic belt connected to both ends of the elastic belt by a crank arm articulated at B and the angle of rotation = 225 degrees. And the coefficient of friction is 0.3 and the latching force is f. Find the necessary F to generate a torque of 350 on the cylinder while it is rotating in the direction shown? Note that s = c = 135mm a = 500mm. 35mmarrow_forwardThe figure shows an internal rim-type brake having an inside rim diameter of 11in and a dimension R of 3.5 in. The shoes have a face width of 1.25 in. Find the braking torque and the maximum pressure for each shoe if the actuating force is 205 Ibf, the drum rotation is counterclockwise, and f=0.32. The maximum pressure on the right-hand shoe parp is [ 16.99] @ psi. The maximum pressure on the left-hand shoe pa| H is [100.813 | @ psi. The torque on the right-hand shoe Tgis [ .056 | @ kipin. The torque on the left-hand shoe T is [ .332| @ kipin. Total braking torque Tiotal s [-3887] @ Kip-in.arrow_forwardTwo pulleys, one 650 mm diameter and the other 400 mm diameter, on parallel shafts 1.5 m apart are connected by a flat belt. Find the length of the belt required and the angle of contact between the belt and each pulley. What power can be transmitted by the belt when the larger pulley rotates at 1200 rev/min, if the maximum permissible tension in the belt is 10 kN, and the coefficient of friction between the belt and pulley is 0.05? dont write handwritten solution.arrow_forward
- (3) A single-threaded jackscrew has square threads. The screw diameter is l in. and there are 4 threads/in. A friction collar has a 2-in. outside diameter and an l-in. inside diameter. The coefficient of friction is 0.1 for the collar and 0.15 for the threads. How much force must be applied on a l2-in. (radius) jack lever to raise a load of 1,000lb?arrow_forwardFor the drum brake shown in the following figure, there is an inner rim diameter of 280 mm and dimension a = 90 mm. The shoes have a face width of 30 mm. The force exerted by the cylinder hydraulic is 1000 N and the average coefficient of friction is 0.3. Determine: a) The maximum pressure in each shoe; b) The braking torque; c) Reactions resulting from the pivot pin;arrow_forwardSymmetrical shoes will not create moment around the joint The position of the pads with an angle of 90° on the brake where it is placed in the figure is shown in the figure. The brake mechanism is fixed to the ground by the support plate. The disc in the figure rotates clockwise and the friction coefficient of the pads is accepted as 0.491. If a force of 565 N is applied on the arm from the point shown on the figure;a) What is the dimension e shown in the figure so that the shoe does not create a moment around the joint?how much should it be? Calculate.b) Draw free body diagrams of ABC opening lever and both lining levers.c) What is the normal force acting on each pad? How much braking torqueoccurs? calculatearrow_forward
- 8. Design a clamp coupling for transmitting 25 kW at 300 rpm. Allowable shear stresses in shaft and key are 50 MPa and 45 MPa, respectively. The number of bolts joining the two halves of muff is 4. The permissible tensile stress in the bolt is 70 MPa and the permissible crushing stress in the key is 90 MPa. The coeffi cient of friction between the muff of the CI and the shaft of steel is 0.20.arrow_forwardA double square threaded power screw has an efficiency of 65% when raising a load. Friction angle for threads is 8.54o, with collar friction negligible. The pitch diameter of the screw is 70 mm. When lowering a load, a uniform speed is maintained by a brake. If the load is 10 tons, what torque must be exerted by the brake? Is this screw self-locking?arrow_forwardThe roughly position of the automobile jack shown in the figure is a square screw with a single blade at both ends. ABC is controlled by a bolt (right-hand threaded in A, left-handed in C). square of the bolt screw has a pitch of 2.5 mm and an average diameter of 9 mm. between the bolt and the jack limbs The coefficient of static friction is 0.15, taking into account the position and load shown, you can use the jack Find the magnitude of the torque that must be applied to raise it.arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY