Paper shredder

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Image:Paper_shredder.jpg

Contents

Product Dissection

Conventional and Unconventional Purposes:

Shreds paper or credit cards placed correctly into feeder

  • Increase security - not able to easily retrieve information from shredded items
  • Facilitate disposal - reduce volume of garbage
  • Substitute for a recycling bin - provide a seperate container for paper wastes
  • Produce confetti - save money on party decorations

Inputs/Outputs:

  • Material Inputs: Paper, Staples, Credit Cards (no ties)
  • Information Inputs: Direction of motor rotation
  • Energy Inputs: 120V AC
  • Material Outputs: Shredded material inputs
  • Information Outputs: Operation status
  • Energy Outputs: Heat, Noise, Light

Stake Holders:

  • Possible outsourced companies (computer chips, bulbs, motor)
  • Raw materials suppliers
  • Retail stores
  • Transportation workers
  • Stock holders

Operation Procedures:

  • If stored without power cord plugged into electrical wall outlet
    • Position basket in desired place (making sure it is close to an outlet)
    • Place shredder assembly on top of basket
    • Confirm the off/auto/reverse switch is in the off position
    • Plug power cord from shredder assembly into the wall outlet
  • If stored in the off position or continuing from un-powered storage
    • Set off/auto/reverse switch to auto
  • Identify the items for shredding, confirming acceptable destruction
    • Documents(s)
    • Credit Card
  • Confirm dimensions of items to be shredded
    • There is not more than a thickness of 8 pieces of paper
    • There is not more than one credit card
  • Orient items for better control when feeding them into the shredder
    • Align documents
    • Fold/unfold documents
    • Orient credit card to be fed long-ways
  • Confirm that the “ready light” is illuminated
  • Feed item into proper opening
    • Position document(s) in proper groove
    • Position credit card in proper slot
  • Action following feeding
    • Let go of document(s) once feeder has caught them, allowing them to be pulled through automatically
    • Continue pressing credit card downwards until no longer possible
  • If finished shredding, return to desired storage conditions
    • If placing in desired storage area
      • Turn off shredder
      • Unplug power cord from wall outlet
      • Pick up shredder assembly or shredder assembly and basket, placing it where desired
    • If leaving in desired spot
      • Can leave in auto position, off position, or off position with power cord unplugged from wall outlet

Specific User Considerations:

  • Certain tasks difficult for people with a neural disorder and/or coordination difficulty
    • Feeding tasks
    • Switch control
  • Bending over to feed items difficult for individuals with orthopedic (e.g. back) and/or balance problems
  • Inconvenient and inefficient for large corporate tasks
  • Main shredder assembly is heavy and possibly difficult to lift for weaker individuals
    • Main shredder assembly must be lifted when emptying basket and setting up
    • Main shredder assembly may often be moved depending on storage preference

Areas of Possible Improvement:

  • Very noisy
  • Heat generation
  • Improved shredding for added security
  • Wall-mounting capability
  • Weight issues of shredder assembly which affect portability, storage, and emptying waste basket
  • Improved feeding capabilities
    • Large queue where can position multiple sheets that will automatically feed

Functional Operation:

There are three switches in the electrical circuit that must be activated to begin shredding. First, the shredder must be properly resting on the waste bin to toggle the safety switch, and then the off/auto/reverse switch that allows power to go to the shredder must be moved to "auto". Finally, the paper being put into the shredder compresses an air damper which trips the third switch and sends power to the AC motor. The damper slowly depresses and when it is fully extended the switch is released, terminating the shredding process. The AC motor drives a gear train that reduces the speed of the shaft rotation and increases the torque. The first two gears are helical gears in order to reduce noise. At the end of the gear train, two spur gears are meshed and attached to individual shafts with cross-hatching blades. The blades are in a wave shape that cuts paper into the desired diamond shaped shreds. The blades spin in opposite directions and the paper is fed in between the spinning blades. The shredded paper falls into basket.

Media:

For videos of user-trials and general operation, please visit the following: http://www.youtube.com/view_play_list?p=501153C70A89F93B

Components:

| class="wikitable" border="1" |- ! Part # !! Part name !! QTY !! Function !! Materials !! Dimensions !! Manufacturing Process !! Picture |- | 001 || Top Cover || 1 ||

  • Protect the user from moving parts
  • Aesthetics
  • Support the shredder on basket
  • Houses the on/off switch
  • Informs the user of acceptable inputs
  • Houses item entrance for shredding

|| Plastic || 12" x 5" x 1" || Injection Molding || |- | 002 || Switch Housing || 1 ||

  • Sets desired functionality
  • Houses child safety button

|| Plastic || 3" x 1" x 1" || Injection Molding || |- | 003 || Base || 1 ||

  • Houses main components
    • Lightbulb
    • Motor
    • Gear train
    • Blades
    • Operation safety switch
  • Dispense of shredded paper

|| Plastic || 12" x 5" x 3" || Injection Molding || |- |004 || Feeder Lip Top || 1 ||

  • Guides paper
  • Protects user

|| Plastic || 8" x 2" x 1" || Injection Molding || |- |005 || Feeder Lip Bottom || 1 ||

  • Guides paper
  • Protects user

|| Plastic || 8" x 2" x 1" || Injection Molding ||

|- |006 || Child Safety || 1 ||

  • Prevents unintentional use

|| Plastic || 2" x 1" x 1" || Injection Molding ||

|- |007 || Electrical & Motor Sub-assembly || 1 ||

  • Drives gear train (motor)
  • Automatic safety switch (must be sitting on basket properly)
  • Shredding cutoff time-delay
  • Ready LED
  • Off/auto/reverse switch
  • Light bulb
  • Provides electrical power to the system

|| N/A || N/A || N/A ||

|- |008 || Helical Gear || 1 ||

  • Component of gear train
  • Conects to motor
  • Quieter than spur gears

|| Plastic || 1" x 1" || Injection Molding ||

|- |009 || Large Spur Gear || 1 ||

  • Component of gear train
  • Reduce Speed/Increas Torque

|| Plastic || 3" x 1" || Injection Molding ||

|- |010 || Small Spur Gear || 1 ||

  • Component of gear train
  • Reduce Speed/Increas Torque

|| Plastic || 1" x 1" || Injection Molding ||

|- |011 || Output Spur Gear || 1 ||

  • Drive shaft

|| Plastic || 1" x 1" || Injection Molding ||

|- |012 || Light Bulb Reflector || 1 ||

  • Increases intensity of light

|| Plastic+Aluminum || .5" x .5" x 1" || Injection Molding and Sheet Foil||

|- |013 || Delay Trigger Housing || 1 ||

  • Houses the shredding cutoff time-delay

|| Plastic || 3" x 1" x 1" || Injection Molding ||

|- |014 || Cutoff Switch Time-Delay Trigger || 1 ||

  • Triggers cutoff switch time-delay

|| Plastic || 1" x 1" x .5" || Injection Molding ||

|- |015 || Spring for Child Safety Switch || 1 ||

  • Hold the safety switch in position

|| Spring Steel || 1/8" x .5" || Winding ||

|- |016 || Bow-Tie Washer || 1 ||

  • Attaches auotmatic safety switch to the base cover

|| Plastic || 1" x 1" x 1/8" || Injection Molding ||

|- |017 || Main Shaft Base Plate || 1 ||

  • Hold axes aligned

|| Plastic || 3" x 3" x 1/4" || Injection Molding ||

|- |018 || Cover Plate for Shaft Alignment || 1 ||

  • Hold axes aligned

|| Plastic || 2" x 2" x 1/4" || Injection Molding ||

|- |019 || Gear Train Housing Base Plate || 1 ||

  • Holds gears
  • Holds axes aligned

|| Metal || 4" x 2" x 1/4" || Stamped ||

|- |020 || Gear Train Housing Top Plate || 1 ||

  • Holds gears
  • Holds axes aligned

|| Metal || 3" x 1" x 1/4" || Stamped ||

|- |021 || Attachment Aligner for Motor Base Plate || 1 ||

  • Holds motor to gear train housing top plate

|| Plastic || 1" x 1" x 1/4" || Injection Molding || |- |022 || Screws || 31 ||

  • Fastening

|| Steel || #10-20 || Machined|| In the background

|- |023 || Helical Blade || 104 ||

  • Cut paper in diamond shape
  • Feeds paper

|| Steel || .5" x 1\32" || Stamped ||

|- |024 || Flat Blade || 8 ||

  • Feeds paper

|| Steel || .5" x 1\32" || Stamped ||

|- |025 || Paper Aligners || 54 ||

  • Ensures proper feeding of paper

|| Plastic || 1/2" x 1/4" x 1" || Injection Molding ||

|- |026 || "Paper Aligner" Aligning Rod || 2 ||

  • Aligns aligners

|| Metal || 1\4" x 8" || Extrusion || Gold rod

|- |027 || Long Main Shaft || 1 ||

  • Driven by gear train
  • Turns blades
  • Aligns blades

|| Steel || 10" x 1/4" || Machined|| Center rod

|- |028 || Short Main Shaft || 1 ||

  • Driven by gear train
  • Turns blades
  • Aligns blades

|| Steel || 9" x 1/4" || Machined|| Center rod

|- |029 || Basket || 1 ||

  • Collect shredded waste
  • Houses tab
  • Shredder assembly rests on top of basket
  • Keeps shredder assembly aligned

|| Steel || 12" x 12" x 5" || Stamp ||

|- |030 || Tab || 1 ||

  • Press safety switch

|| Steel || 1/2" x 1/2" x 1/2" || Stamped || On the basket

|-}

Retrieved from "https://wiki.ece.cmu.edu/ddl/index.php/Paper_shredder"
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