Known: Definitions of the words science, engineering, and design are given in Section 1.1 Find: Write definitions of above words using a dictionary and compare with those given in Section 1.1 Analysis: 1. According to Webster's Ninth New Collegiate Dictionary, science is the knowledge covering general truths or the operation of general laws especially as obtained and tested through scientific method. According to Section 1.1, science is concerned with uncovering basic knowledge. 2. According to Webster's Ninth New Collegiate Dictionary, engineering is the application of science and mathematics by which the properties of matter and the sources of energy in nature are made useful to people in structures, machines, products, systems, and processes. According to Section 1.1, engineering is an applied science, in the sense that it is concerned with understanding scientific principles and applying them to achieve a designated goal utilizing the resources and laws of nature to benefit humanity 3. According to Webster's Ninth New Collegiate Dictionary, art is a skill acquired by experience, study, or observation. (Also, art is defined as the conscious use of skill and creative imagination, especially in the production of aesthetic objects.) 4. According to Webster's Ninth New Collegiate Dictionary, design is an act of devising for a specific function or end. According to Section 1.1, mechanical engineering design deals with the conception, design, development, refinement, and application of machines and mechanical apparatus of all kinds. SOLUTION (1.2) Known: Safety devices are found in machines used in automatic production operations. These safety devices stop the machine when a faulty operation takes place. Find: Describe and sketch several mechanical safety devices. Analysis: An initial search of the patent literature at http://patent.womplex.ibm. com for mechanical safety devices yielded (1) a chain saw cutting chain safety stop and (2) a safety stop switch for the control unit for a marine engine: (1) US4651423: Chain saw cutting chain safety stop Disclosed is a safety stop that is operatively connected to the existing rotatively mounted front handle of a chain saw to independently actuate such safety stop to its actuated position to stop the rotation of the cutting chain upon rotation of such rotatively mounted front handle either automatically when "kick-back” occurs or upon such rotation by the operator at his option 1ae po UY (lee as erey 77 7 Vi : (2) US4250358: C ‘it for marine engines employing safety stop switch A safety stop switch for a marine engine includes a control unit housing, and a normally closed, single throw toggle switch mounted on the housing and including a switch arm extending away from the housing to permit operation of the switch between closed and open positions. The switch is electrically connected to the engine to interrupt engine operation when switched to the open position. A hood extends from the periphery of the housing and covers the switch arm when in the closed position, and has a peripheral lip which is spaced from the switch arm a dimension which is less than the thickness of a key which encircles the switch arm. A lanyard is connected to the key and to the boat operator, and upon the exertion of a force on the lanyard, the key pulls the switch arm down into the open position, thereby interrupting operation of the marine engineComments: 1. With additional effort, safety devices for automatic production operation should be found. 2. For additional safety devices see Mechanical Details for Product Design, Douglas C. Greenwood, editor, McGraw-Hill Book Company, New York, 1964.SOLUTION (1.3D) Known: The OSHA regulations are found at http://www.osha.gov. Find: List methods used to guard machine hazards. Give conditions where guards should be used. Analysis: The Code of Federal Regulations, Title 29--Labor, § 1910.212 lists general requirements for all machines: (a) Machine guari 1) Types of guarding. One or more methods of machine guarding shall be provided to protect the operator and other employees in the machine area from hazards such as those created by point of operation, ingoing nip points, rotating parts, flying chips and sparks. Examples of guarding methods are-barrier guards, two-hand tripping devices,electronic safety devices, etc. (2) General requirements for machine guards. Guards shall be affixed to the machine where possible and secured elsewhere if for any reason attachment to the machine is not possible. The guard shall be such that it does not offer an accident hazard in itself. (3) Point of operation guarding. (i) Point of operation is the area on a machine where work is actually performed upon the material being processed. (ii) The point of operation of machines whose operation exposes an employee to injury, shall be guarded. The guarding device shall be in conformity with any appropriate standards therefor, or, in the absence of applicable specific standards, shall be so designed and constructed as to prevent the operator from having any part of his body in the danger zone during the operating cycle. (ii) Special handtools for placing and removing material shall be such as to permit easy handling of material without the operator placing a hand in the danger zone. Such tools shall not be in lieu of other guarding required by this section, but can only be used to supplement protection provided (iv) The following are some of the machines which usually require point of operation guarding: (a) Guillotine cutters. (b) Shears. (c) Alligator shears. (d) Power presses. (e) Milling machines. (£) Power saws. (g) Jointers. (h) Portable power tools. (i) Forming rolls and calenders. (4) Barrels, containers, and drums. Revolving drums, bartels, and containers shall be guarded by an enclosure which is interlocked with the drive mechanism, so that the barrel, drum, or container cannot revolve unless the guard enclosure is in place. (5) Exposure of blades. When the periphery of the blades of a fan is less than seven (7) feet above the floor or working level, the blades shall be guarded. The guard shall have openings no larger than one-half (1/2) inch. (b) Anchoring fixed machinery. Machines designed for a fixed location shall be securely anchored to prevent walking or moving. 14SOLUTION (1.4D) Known: The web site http://www.nssn.org lists titles and organizations for standards. Find: List titles and organizations for standards on (a) machine guarding, (b) refuse vebicles, and (c) portable grinders. Analysis: TABLE OF ORGANIZATIONS AND STANDARDS Organization ‘Standards (@) machine guarding _|U.S. Government Code of Federal (OSHA) Regulations, Title 29-- Labor, § 1910.212 (b) refuse vehicles ‘American National [ANSI 2245.1 Standards Institute (©) portable grinders ‘American National ANSI B71 (abrasive Standards Institute wheels) U.S. Government Code of Federal (OSHA) Regulations, §1926.303 (abrasive wheels and tools) SOLUTION (1.12D) Known: An essay must be written. Find: Write an essay titled "What Makes a Sucessful Design Engineer?" Analysis: 1. This exercise is left to the student. 2. For comparison, an article by George H. Logan published in 1959, in Product Engineering Design Manual, edited by Douglas C. Greenwood, McGraw-Hill Book Company, New York, p. ix suggests the following: A design engineer must have the inner spark that urges him to obtain the inner satisfaction linked with achievement. The designer should look for unorthodox approaches to problems. The design engineer should be able to control his mind to allow for clear and unobstructed thinking. The designer should believe in and practice work organization. An engineer who lacks organization can waste much time through imperfect understanding of what the project is supposed to produce. The engineer should discipline his mind, control his speech and actions so that he achieves full emotional balance. Building a calm temperament is not always easy, but it can be done if restraint is practiced. The importance of broadening the knowledge of non-technical business topics should not be overlooked. The engineer must be able to make quick decisions that are correct most of the time and the creative design engineer can make for himself an opportunity that leads to an outstanding position in his chosen field.