Mechanical Technology Grade 12 Chapter 3 Safety In The Workshop


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This slide show accompanies the learner guide "Mechanical Technology Grade 10" by Charles Goodwin, Andre Lategan & Daniel Meyer, published by Future Managers Pty Ltd. For more information visit our website

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Mechanical Technology Grade 12 Chapter 3 Safety In The Workshop

  2. 2. DEFINING AN ACCIDENT <ul><li>An accident is an unplanned, uncontrolled event caused by unsafe acts and unsafe conditions. </li></ul><ul><li>All South African safety regulations are based on the Occupational Health and Safety (OHS) Act No. 85 of 1993. </li></ul>
  3. 3. What are the causes of accidents? <ul><li>Poor housekeeping </li></ul><ul><li>Loose clothing </li></ul><ul><li>Improper use of tools </li></ul><ul><li>Inaccurate setting-up of machines </li></ul>
  4. 4. House Keeping <ul><li>Good housekeeping means working tidily and orderly. </li></ul><ul><li>Always work neatly and return materials and tools to their proper places. </li></ul><ul><li>Keep working areas unobstructed at all times; when using a machine, keep an unobstructed space (of 2,25 m2) around the machine. </li></ul><ul><li>Grease, oil, tools, loose objects and materials lying around can easily cause a fall. </li></ul><ul><li>A clean, orderly workshop is a safe workshop. </li></ul><ul><li>Also maintain floors, walkways, stairways and gangways, ensuring they are skidfree (and leak-free) and clear of obstructions. </li></ul>
  5. 5. House Keeping
  6. 6. Protective clothing
  7. 7. Protective clothing <ul><li>When welding, you need to protect your eyes and respiratory system, as well as your body and your clothing. </li></ul><ul><li>You should protect yourself against heat, flying particles that are incandescent (glowing with heat) and radiation. </li></ul><ul><li>You should always: </li></ul><ul><li>wear safety goggles when using a grinding machine or lathe, or when chipping </li></ul><ul><li>not wear loose clothing, jewellery, ornaments, a watch or key chain, or a strap when working close to moving machinery.   </li></ul>
  8. 8. Bench Work
  9. 9. Bench Work <ul><li>THE ACT REFERS TO THESE PRECAUTIONS: </li></ul><ul><li>Make sure that sharp points of tools and material do not stick out from your workbench. </li></ul><ul><li>When chipping metal with a chisel, chip in a direction so that cut-off material cannot hit anyone. </li></ul><ul><li>For your own protection, use a guard where necessary. </li></ul><ul><li>Do not use chisels with mushroomed heads. </li></ul><ul><li>Ensure that rolling stock cannot roll off the workbench and injure your feet. Also place heavy objects away from the edge of the bench so that they don’t fall. </li></ul>
  10. 10. Bench Work <ul><li>Right-handed people should cut with a hacksaw on the right-hand side of the vice. If the blade breaks, your hand will move safely away from the vice and the work piece. </li></ul><ul><li>Ensure that files have handles. </li></ul><ul><li>When using a hammer make sure the head is securely fixed. </li></ul><ul><li>Don’t put sharp or pointed tools in your pockets. </li></ul><ul><li>Don’t strike hard metals directly with a hammer – the metal may splinter and injure someone. </li></ul><ul><li>Place a piece of soft material (such as copper) over the metal to act as a shield. </li></ul>
  11. 11. Bench Work <ul><li>You should always: </li></ul><ul><li>Wear safety goggles when using a grinding machine or lathe, or when chipping </li></ul><ul><li>Do not wear loose clothing, jewellery, ornaments, a watch or key chain, or a strap when working close to moving machinery. </li></ul>
  12. 12. Assessment <ul><li>Name five safety precautions to observe when working at a workbench. </li></ul><ul><li>Pg 22 </li></ul>
  13. 13. Bench Grinder
  14. 14. Bench Grinder <ul><li>Only use a machine once the guards are correctly fitted. </li></ul><ul><li>Check that there is no oil or grease on the floor around the machine. </li></ul><ul><li>Check that the tool rest is not more than 3 mm from the grinding wheel surface. </li></ul><ul><li>When starting the machine, don’t stand in front of the wheel. Before you start grinding, let the machine idle for a few seconds. </li></ul><ul><li>If the wheel is running unevenly, dress it with an emery-wheel dresser. </li></ul><ul><li>Grind only on the face of a straight grinding wheel and never on the side. Use the various wheels only for their intended purpose. </li></ul>
  15. 15. Bench Grinder <ul><li>Approach the wheel carefully and gradually, and don’t ‘jab’ materials onto it. </li></ul><ul><li>Never ‘force grind’ so that you slow or stop the motor. </li></ul><ul><li>Adjust the tool rest only when the wheel is stationary. </li></ul><ul><li>Clamp work pieces and holding devices safety and firmly. </li></ul><ul><li>Never allow the wheel to stand in cutting fluid as this may cause it to run ‘off balance’ when you switch it on again </li></ul>
  16. 16. Grinding Wheels <ul><li>All power-operated grinding machines should be clearly marked with the recommended speed (in revolutions per minute) of the spindle. </li></ul><ul><li>This speed should not allow the peripheral speed of the wheel to exceed the manufacturer’s recommendation. </li></ul><ul><li>Every grinding wheel should have a guard that can withstand the force of a rupturing wheel. </li></ul><ul><li>Bench grinders should have a transparent shield to protect an operator’s eyes. </li></ul><ul><li>Each machine must carry a notice prohibiting persons from performing, inspecting or observing grinding work without suitable protection for the eyes. </li></ul>
  17. 17. Mounting of a Grinding Wheel <ul><li>Select the correct type of wheel for the job. </li></ul><ul><li>Inspect the wheel for cracks and tap it to apply the ‘ringing test’. </li></ul><ul><li>Never use a grinding wheel which is damaged or which is not properly dressed. </li></ul><ul><li>Make sure that the wheel’s speed does not exceed the manufacturer’s recommendation. </li></ul><ul><li>On the left is an example of a manufacturer’s recommendation. </li></ul><ul><li>Never force the wheel onto the spindle. </li></ul><ul><li>Use only one smooth paper spacer on each side of the wheel. </li></ul>
  18. 18. Mounting of a Grinding Wheel <ul><li>Use true and correctly recessed flanges of the same size and at least one third the diameter of the wheel. </li></ul><ul><li>Gently tighten the grinding wheel with a spanner only enough to hold it firmly. </li></ul><ul><li>Replace the guards correctly. </li></ul><ul><li>Stand aside and set the machine in motion. Let the machine idle before you dress the wheel, using an emery-wheel dresser. </li></ul><ul><li>Finally stop the machine and reset the tool rest to within 2 mm of the wheel surface. Ensure that the tool rest is parallel to the wheel surface. </li></ul>
  19. 19. Grinders <ul><li>Every grinding wheel should have a guard that can withstand the force of a rupturing wheel. </li></ul><ul><li>Bench grinders should have a transparent shield to protect an operator’s eyes. </li></ul><ul><li>Each machine must carry a notice prohibiting persons from performing, inspecting or observing grinding work without suitable protection for the eyes. </li></ul>
  20. 20. Assessment <ul><li>Name five safety precautions to observe when working with a grinding wheel. </li></ul><ul><li>Name five steps to follow when installing a grinding wheel. </li></ul><ul><li>Pg 25 </li></ul>
  21. 21. Drill Press
  22. 22. Drill Press <ul><li>Always observe the following: </li></ul><ul><li>Choose the correctly sharpened drill for the type of work you need to do and the material you are about to drill. </li></ul><ul><li>Do not leave the key in the chuck when you are not at the machine. </li></ul><ul><li>Never leave the machine running if unattended. </li></ul><ul><li>Clamp the work piece securely to the table and do not hold it by hand. </li></ul><ul><li>Never attempt to stop the work piece by hand if it slips from the clamp. </li></ul>
  23. 23. Drill Press <ul><li>A drill should run at the correct speed for the job. </li></ul><ul><li>Don’t force a drill into the work piece – this may cause broken or splintered drills and possible injury. </li></ul><ul><li>Use a brush or wooden rod to remove chips from the drill – and not your fingers, waste or rags. </li></ul><ul><li>When reaching around a revolving drill, be careful that your clothes do not get caught in the drill or drill chuck. </li></ul>
  24. 24. Portable Electric Tools <ul><li>Portable electric tools must be earthed if they are not double insulated. </li></ul><ul><li>They should be correctly maintained. </li></ul><ul><li>Their flexible cords should be undamaged and their plugs in good order. </li></ul>
  25. 25. Milling Machine and Lathe
  26. 26. Milling Machine and Lathe <ul><li>Observe the following precautions: </li></ul><ul><li>Make sure that all guards are in place. </li></ul><ul><li>Don’t use a machine or come close to its moving parts while wearing loose clothing. Keep any cleaning material such as waste and rags away from rotating parts. </li></ul><ul><li>Check that there is no oil or grease on the floor around the machine. </li></ul><ul><li>Don’t leave spanners or keys on rotary parts. Always disconnect, remove or stand clear of hand wheels, levers or chuck keys before setting your machine or feeds in motion. </li></ul>
  27. 27. Milling Machine and Lathe <ul><li>Never apply a wrench to revolving work. </li></ul><ul><li>Always clamp work pieces and holding devices safely and firmly. A loose fit, especially of spanners and keys, may cause slipping and result in injury. </li></ul><ul><li>Do not use your hands to remove cuttings while a machine is in motion. Use a wire hook or a brush once the machine has stopped. </li></ul><ul><li>Never adjust the cutting tool while a machine is running. </li></ul>
  28. 28. Milling Machine and Lathe <ul><li>Resist the habit of leaning on machinery. This dangerous ‘automatic’ practice often results in serious injury. </li></ul><ul><li>Don’t attempt to stop a machine by placing your hand on the chuck while the machine is slowing down. </li></ul><ul><li>Give attention to cutting-fluid control before switching on a machine. </li></ul>
  29. 29. Assessment <ul><li>Name four safety precautions to follow when working with a lathe or a milling machine. </li></ul><ul><li>Name five safety precautions to follow when working with a drill press. </li></ul><ul><li>State two safety precautions for each of the following: </li></ul><ul><ul><li>transmission belts </li></ul></ul><ul><ul><li>projecting shaft ends </li></ul></ul><ul><ul><li>revolving shafts </li></ul></ul><ul><ul><li>general machine protection. </li></ul></ul><ul><li>Pg 27 </li></ul>
  30. 30. Shears, Guillotines and Presses <ul><li>Where the opening at the point of operation (cutting) of a pair of shears, or a guillotine or a press is greater than 10 mm, the machine should have either a fixed guard which prevents hands or fingers reaching through, over, under or around the guard </li></ul><ul><li>A self-adjusting guard which automatically adjusts to the thickness of the material being worked, can also used. </li></ul><ul><li>Some machines have manual or automatic moving guards which completely enclose the point of operation so that the working stroke cannot be opened unless the ram or blade is stationary. </li></ul>
  31. 31. Shears, Guillotines and Presses <ul><li>Another safety device is the automatic sweep-away or push-away which pushes any part of the operator’s body out of the danger zone when the working stroke starts. </li></ul><ul><li>Today there are electronic presence-sensing devices which stop the working stroke if the device senses any foreign object in the danger zone. </li></ul>
  32. 32. Stacking Articles <ul><li>Stacks which consist of successive </li></ul><ul><li>tiers on top of one another should not </li></ul><ul><li>be built unless: </li></ul><ul><li>they are under the personal supervision of a qualified person </li></ul><ul><li>the base is level and strong enough </li></ul><ul><li>the articles in the lower tiers are capable of carrying the weight of the articles stacked above them </li></ul>
  33. 33. Stacking Articles
  34. 34. Stacking Articles <ul><li>Stacks should also not be built unless: </li></ul><ul><li>all the articles in a single tier are of the same size, shape and mass </li></ul><ul><li>pallets and containers are in good condition </li></ul><ul><li>the support structure used for the stacking is structurally satisfactory to support the articles to be stacked on it </li></ul>
  35. 35. Stacking Articles
  36. 36. Stacking Articles <ul><li>An employer must ensure that: </li></ul><ul><li>persons engaged in stacking operations are safe </li></ul><ul><li>stacks that are in danger of collapsing are dismantled immediately </li></ul><ul><li>the stability of stacks is not endangered by vehicles or other machinery or persons moving past them. </li></ul>
  37. 37. Assessment <ul><li>Name four safety precautions that must be observed when considering each of the following: </li></ul><ul><ul><li>stacking of articles </li></ul></ul><ul><ul><li>ventilation lighting </li></ul></ul><ul><ul><li>machine tools </li></ul></ul><ul><ul><li>arc welding and gas welding. </li></ul></ul><ul><li>Pg 29 </li></ul>
  38. 38. Responsibility <ul><li>The Act places the person in charge of machinery responsible for safety. This person must: </li></ul><ul><li>Install and properly maintain the machine </li></ul><ul><li>Repair machinery </li></ul><ul><li>Ensure that safety appliances, devices and guards are in good condition and properly used </li></ul><ul><li>Stop anyone from using a dangerous machine. </li></ul>
  39. 39. Obedience to Instructions <ul><li>Use machines according to the manufacturers’ instructions. </li></ul><ul><li>Don’t use a machine without your teacher’s supervision </li></ul>
  40. 40. Restricted Admittance <ul><li>Only people authorised by the user or entitled by law should enter a workshop. Each workshop should have a notice announcing this ruling . </li></ul>
  41. 41. Floors <ul><li>All workshop floors should be level, clean, non-slippery and, as far as possible, free from chips or loose material. </li></ul>
  42. 42. Lighting <ul><li>There must be adequate illumination (lighting) in the workplace. </li></ul><ul><li>The glare in any workplace must be reduced to a level that does not impair vision. </li></ul><ul><li>The lighting on rotating machinery must not cause a stroboscopic (flashing) effect. </li></ul><ul><li>Lights and lamps must be kept clean and maintained. </li></ul><ul><li>Artificial light must not shine in a machine operator’s eyes. </li></ul>
  43. 43. Dangerous Places <ul><li>All elevated platforms, openings in floors, pits, trap holes and other dangerous places should be securely fenced or protected to prevent accidents. </li></ul>
  44. 44. First aid, emergency equipment and procedures <ul><li>Injuries and emergencies should be dealt with swiftly and carefully. </li></ul><ul><li>Where more than five employees are employed at a workplace, the employer must provide an accessible first aid box. </li></ul><ul><li>The Act states what the box should contain and that the whereabouts of the first aid box be clearly sign-posted. </li></ul>
  45. 45. Assessment <ul><li>State two safety precautions to be observed when practising first aid in a workplace. </li></ul><ul><li>Pg 30 </li></ul>
  46. 46. Colour coding and signs <ul><li>All colours are based on the SANS Code 1091 colour coding. </li></ul>
  47. 47. Colour coding <ul><li>Blue </li></ul><ul><li>The colour blue is used as a colour-code indicator on pipelines carrying drinkable water and should not be used on machinery. </li></ul><ul><li>Green </li></ul><ul><li>Emerald green is used to identify: </li></ul><ul><li>the location of first aid equipment </li></ul><ul><li>emergency exits and safety areas </li></ul><ul><li>informatory signs (such as signs for toilets and parking areas) </li></ul><ul><li>starting devices on electrical equipment </li></ul><ul><li>miscellaneous safety conditions. </li></ul>
  48. 48. Colour coding <ul><li>Red </li></ul><ul><li>Signal red is used to identify: </li></ul><ul><li>Danger </li></ul><ul><li>fire protection </li></ul><ul><li>stopping devices. </li></ul><ul><li>Yellow </li></ul><ul><li>Yellow is used for housekeeping markings such as identifying crane lifting hooks, </li></ul><ul><li>changes in floor level and similar tripping hazards, and low head room, </li></ul><ul><li>indicate ‘No parking’ areas on the floor below fire equipment and electrical switchgear panels . </li></ul>
  49. 49. Colour coding <ul><li>Orange </li></ul><ul><li>The colour orange is used to identify: </li></ul><ul><li>electrical switchgear </li></ul><ul><li>electrical services </li></ul><ul><li>exposed and rotating machine parts (for example if a casing or guard is not completely closed). </li></ul>
  50. 50. Assessment <ul><li>Name the five basic colours that are used to give information in the </li></ul><ul><li>workplace, and give three examples of this colour coding. </li></ul><ul><li>Pg 32 </li></ul>