User:JessicaHibbert

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Bucknell Mechanical Design Home

Contents

Black & Decker Drill Dissection

Figure 1: Black & Decker Drill Before Disassembly
Figure 2: Black & Decker Drill Control Top












Function

The function of the Black & Decker Light Weight Cordless Drill is to drill screws. The advantage of this battery powered tool is to offer more power than manual screw drivers. Furthermore, the toold is hand-held and lightweight for ease in use and storage.



User Requirements

  • Motors strong enough to create enough torque to drill screw
  • Small and handheld for ease of use
  • Efficient battery use so the battery life will be long enough
  • Ergonomic design for long use
  • Noise Control



Possible Engineering Specifications

  • Powered by 6V (4 AA batteries) – long battery life
  • Maximum Torque for Battery Power, high torque rating
  • Powerful motor
  • How the planetary gears are set up as well as the material they are made of
  • Low Cost maximizes manufacturer profit, use plastic frame and gears, only using metal for parts that needed to be the strongest
  • Lightweight --- due to utilization of plastic materials
  • Using lube – minimize noise control



How It Drills

The motor uses the energy from four 1.5V AA batteries to generate power. This power turns the drive shaft of the drill. This drive shaft is then connected to two planetary gear systems. The second of these gear systems powers and turns the end drill bit shaft. The drill bit shaft is what rotates the inserted drill bit and consequently the screw.


1) The motor is powered by four 1.5V AA batteries.

Figure 3: AA Alkaline Battery
Figure 4: Four AA Alkaline Batteries in Casing






















2) The motor then turns the drive shaft of the drill.

Figure 5: Motor of the Black & Decker Drill
Figure 6: Drive Shaft of the Motor














3) The drive shaft is connected to the first of two planetary gear sets. These planetary gears are used to decrease the angular velocity created by the rotating motor shaft. This therefore increases the amount of torque that will be exerted by the drill bit.

Figure 7: One of Two Planetary Gear Systems Connected to Arm
Figure 8: Planetary Gears Outside of Shaft and Arm Connection














4) Finally, the torque created by the rotating drill shaft is transferred to screw through the rotating drill shaft and bit.

Figure 9: Casing of Drill Shaft
Figure 10: Drillbit Rotated by Drill Shaft












Parts

The table belows lists the components for the Black & Decker Drill:

Table 1: Black & Decker Drill Component List
Part # Part Name Category Function Material Picture
1 Batteries Power Supply Power 4 AA Batteries in Battery Carried - Alkaline Batteries
Batt2.jpg
2 Motor Power Converts energy necessary to rotate shaft Low grade steel and plastic
Bdmotor.JPG
3 Exterior Casing Frame Ergonomic design to protect interior components and to conform to users hand; controls readily available for pinky and thumb use Plastic with rubber grips
Bdextcasing.JPG
4 Motor Shaft Power Turns planetary gears as well as acts as teh conversion between the motor power and the torque created by the shaft Hardened steel
Bdmshaft.JPG
5 Planetary gear system (double) Torque First set of three is powered by the motor shaft - this set is then connected to a second set of three gears that power the actual drill shaft Both sets of gears are made of plastic - gears closed to drill bit are made of a higher strength plastic - gears further from drill bit are made of lesser quality plastic
Bdplangears1.JPG
6 Arm Torque Convert torque created by the first set of planetary gears to the shaft that goes through the second set of planetary gears Metal
Bdarm1.JPG
Bdarm2.JPG
7 The Drill Shaft Drilling Turns the actual drill bit Metal
Drillshaft.JPG
8 Drill Bit Drilling Drills Metal
Bddrillbit.JPG
9 Outer Gear Setting change Allows user to lock gears and use the drill manually Lower grade plastic
Bdouttergear.JPG