6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith

LEVERSPULLEYS  M.A. = number of strands supporting the load (minus the strand where the force is applied) 6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith 1 st 2 nd 3 rd

Tower Cranes Fixed Stationary; usually erected in place Parts Base Slewing Ring (Turntable) Tower Boom Counterbalance Load Line Lifting Hook 6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Tower Crane

 Used in statistics, physics, chemistry and mechanics  Mechanical DOF  The set of independent translations and/or rotations that describe the position of a body or system 6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Translation – a linear movement without rotation. Rotation – an angular movement about some axis.

6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith 1.Define the Problem 2.Brainstorm, Research, Generate Ideas 3.Explore Possibilities 4.Develop a Design Proposal 5.Make Model/Prototype 6.Test and Evaluate 7.Refine the Design 8.Communicate the Solution In order to define the problem, we need to: Identify the degrees of freedom (DOF) on the system Determine the constraints on each DOF Learn of any external constraints imposed on the system

Tower Crane DOF 6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Turntable (Slewing Ring) What type of motion is it? (rotation, linear) What is the size of the motion? (Fairly large, Fairly small) Can the motion be reversed? (Bi-directional, Unidirectional) *Needs to be simple to construct. Rotation Relatively large motion Bidirectional motion

6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Spur Helical Bevel Rack & Pinion Worm

6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Tension Compression Torsion Clock Clip

6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Disc Geneva Groove Cylinder and End

6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Spur Cranks & Linkages Pulleys Rack & Pinion

Tower Crane DOF 6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Boom What type of motion is it? (rotation, linear) What is the size of the motion? (Fairly large, Fairly small) Can the motion be reversed? (Bi-directional, Unidirectional) *The motion is horizontal. *Needs to be simple to construct. Linear Relatively large motion Bidirectional motion

6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Rack & Pinion Cranks& Linkages Pulleys

Tower Crane DOF 6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Lifting Hook What type of motion is it? (rotation, linear) What is the size of the motion? (Fairly large, Fairly small) Can the motion be reversed? (Bi-directional, Unidirectional) *The motion is vertical. *Needs to be simple to construct. Linear Relatively large motion Bidirectional motion

6/23/2016Baltimore Polytechnic Institute Engineering Practicum – Dr. Smith Pulleys