Group 16 - Black & Decker Drill/Gate 2

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Gate 2

Causes for Corrective Action

The work and management plans have been followed perfectly by the entire team. Following these plans has made the project very manageable for everyone in the group, as all of the work has been split up evenly and fairly.

In the work assessment, all work required for each stage was intended to be completed a few days early to avoid last minute stress. Everything has been accomplished in the designated time frames with time to spare

Each member has followed the management proposal and everyone has fulfilled the duties that their respective position entails. Every member has embraced their responsibilities and is ready for the challenge of the workload ahead.

In order for the team to continue to work as effectively and efficiently as it has thus far, there are a few essential things the group must continue to do. The group must stick to the management and work proposals diligently. The group must also continue to maintain strong communication with one another, keeping up to date with the individual sections being worked on.

Everyone in the group plans on sticking to the management and work proposals for the upcoming parts of the project, and each will strive for it to go as smoothly as the previous stage has gone.

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Product Dissection Plan:

Overview

The Black and Decker hand drill is a sturdy tool. It has been built to ensure that all parts in the product remain in place and do not cause a safety hazard. Although built to last, it is fairly easy to disassemble. To rate the difficulty of disassembly, a scale from ‘1’ to ‘5’, with ‘1’ being the easiest and ‘5’ being the hardest, is used. To give meaning to the scale, a ‘1’ is defined as a simple disassembly, requiring few tools and little time, while a ‘5’ would be a complex process, requiring multiple tools, numerous attempts, and a large amount of time. The disassembly of the Black and Decker hand drill is around a ‘2’ on the scale. Disassembly is not very difficult, as it may become necessary to repair or replace broken and faulty parts.

During pre-disassembly, it was assumed the following would be needed:

1.  3/16 flathead screwdriver
2.  Small pick
3.  Large pick
4.  Needle nose pliers
5.  Small wire cutter
6.  Torx driver set
7.  Vice
8.  Soldering iron

During disassembly, it was found that the following was required:

1.  #12 Torx screwdriver
1.  Needle nose pliers
3.  Allen key

Step-by-Step Process

Each step will be rated in terms of difficulty on a scale from ‘1’ to ‘5’. This is with a ‘1’ being a simple task such as unscrewing something and a ‘5’ being taking apart a piece that is breakable and not easy to get at without care. A “1” will also require less time ( t < min) , prep work, tools, and knowledge of the system, were as a ”4” or “5” can be a more tedious process that requires background knowledge of what the part or product is, and how it has to be disassembled. The background knowledge of the process will act as the determining factor of difficulty.

1. Place the drill on the table, check that it is unplugged and the drill is flat and steady with the Black and Decker label side down.
Difficulty: 1

2. Remove the 9 screws that keep the housing intact using a #12 Torx screwdriver.
Difficulty: 1

3. Remove the top shell of the housing by hand and set it aside.
Difficulty: 1

4. Remove the level cap and rubber drill bit from the inside of the housing. This may require force.
Difficulty: 1

5. Remove the level from the top right corner and the bit holder from the upper middle area. Both components are black in color making them easy to identify against the red shell.
Difficulty: 1

6. Remove the two screws holding the cord clamp using a #12 Torx screwdriver. This clamp is in the central region of the handle. The clamp easily comes off once the screws are taken off.
Difficulty: 1

7. There are two wires connected to the reverse ring on the top right corner. These wires connect the directional switch to the external 120V power supply. The main cord is fastened by compression from the housing at the bottom of the handle. Remove the cord from the slots at the bottom of the handle and remove the two cables inside the housing. Note: Removing the cable is simple, but care must be taken while removing the wires from the reverse ring.
Difficulty: 2

8. Remove the trigger from the shell. Take note of the assembly of the reverse ring and its positioning with the toggle switch and trigger.
Difficulty: 1

9. Remove the directional switch. Be sure to take the left end of the switch out of the lower side of the reverse ring. Once the switch is out, there are no parts held by compression from the housing.
Difficulty: 2

10. Carefully take out the entire arrangement of the reverse ring, motor, fan, gearbox assembly, and keyless chuck from the housing together. As the assembly is held in place by built-in slots in the housing, the assembly should be lifted straight out applying equal force across the each member of the assembly. Note: Perform this step slowly and carefully to ensure the brushes do not fall out or break.
Difficulty: 4

11. Place the assembly on the table and separate the gearbox from the motor; it will pull out with ease.
Video Demonstration: http://www.youtube.com/watch?v=HHbZ2U3iodE
Difficulty: 2

12. Separate the reverse ring from the end on the motor. It is held on by plastic clamps and snaps off easily; care must be taken as the brushes are held in place by the ring with a spring mechanism that pushes them against the motor. Remove the ring and take out the brushes and set them aside.
Difficulty: 3

13. The reverse ring bracket is fastened to the motor by two long screws. Use a #12 Torx screwdriver to remove the screws. The bracket pulls out.
Difficulty: 2

14. The gearbox assembly is made up of four parts: the rear bearing plate, the gear and pinion, front bearing plate, and the spindle attached to the keyless chuck. The four components come off once the gearbox assembly is twisted. This requires little force. After twisting just pull the assembly apart.
Difficulty: 4

15. After step 14 the disassembly is complete. Be sure to take notes on all the parts and label the direction of insertion for the parts. It is suggested to put all small parts such as the screws and the brushes in a bag.

Total Time: 45 minutes

Analysis

If you faced challenges during dissection outline those challenges and describe how they were overcome.

There were very few problems during the disassembly. The following challenges were faced:

1. The chuck could not be taken apart from the spindle. In the attempt to remove the chuck, the chuck was clamped down while an Allen key was inserted and twisted with as much torque as could be produced. After numerous attempts, the chuck could not be successfully removed.
2. The drill was in a non-working condition when handed over to the group. The group believes it has successfully identified the problem in the drill. It was not working due to the broken reverse ring. The group tried to fix it temporarily using insulating tape to hold the two pieces of the reverse ring together. The insulating tape did not work; as soon as it was put back in the assembly, the two pieces broke off again. This problem will try to be resolved in the future by using duct tape or a better option if available. Until then the drill is still in non-working condition.

Is the product intended to be taken apart easily?

As mentioned earlier, the drill is supposed to have a very sturdy build but, as it is a power tool, it is made to be disassembled. Even with the sturdiness it can be disassembled fairly easily which makes repairing/replacing the parts convenient. Common reasons for a consumer to disassemble a drill to repair it would be to replace a burnt out motor in the event of overheating from prolonged use of the drill. The disassembly and replacement of the part can be done by the average consumer in 1 to 2 hours.

What fasteners are used and why?

Fasteners used:

1.  9 #12 torx Screws for the housing.

2.  2 #12 torx screws and a clamp for the cable inside the handle. This is necessary to increase the strength in the cord and prevent it from pulling out of the drill. The clamp counteracts one of the only external components of the drill that is most vulnerable to wear and tear from consumers.

3.  The whole housing is designed with grooves and slots such that the internal mechanical assembly is secured and in place once the two shells of the housing are screwed together.
The #12 torx screw is a common fastener in industry; it has the option to fasten the screw using a small flathead screwdriver or a #12 torx driver. Its design uses more surface area in tightening and torx screws can only be tightened/ loosened using the proper size driver which prevent people from using the wrong size and striping the screw which is common for Philips or flathead screws.

Are special tools required?

The only special tools that are needed to disassemble the drill were the #12 torx screwdriver and the Allen key.

Parts List

Item No.	Part Description	Item No.	Part Description
1	Housing and cover	15	Reverse Ring
2	Spindle	16	Reverse lever
3	Gear	17	VS Switch
4	Washer	18	Cord – 8ft
5	Front Bearing plate	19	Cord protector
6	Keyless chuck	20	Clamp, cord
7	Rear bearing plate assembly	21	Screw
8	Gear and Pinion	22	Screw
9	Armature	23	Name Plate
10	Retaining Ring	24	Brush
11	Washer, Plain	25	Felt washer
12	Heat sink	26	Cap
13	Washer	27	Level
14	Field	28	Bit holder

Video of Parts:http://www.youtube.com/watch?v=vF1B7a0WoYE