Gate 2 - Group 6 2012

Product Dissection

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Introduction

This gate is all about the dissection of the impact wrench. First the Project Management section goes through what each member did for this gate and certain challenges they faced. Then there is a step by step dissection of the tool. This includes pictures and is labeled for ease. Finally there is a section that goes over how the subsections are connected.

Project Management: Preliminary Project Review

Table 1.1: Assessment of the Management Plan

Management Roles	Goals	Successes	Challenges and Resolution
Communication Liaison	Serve as a point of contact for instructors Compose and disseminate communication between group and instructors Compile group input for Gates and prepare preliminary drafts to be reviewed and edited by group members	Resolved miscommunication with instructors regarding the ordering of an electric impact wrench for the group rather than a pneumatic impact wrench Composed group input for Gate 1 into a Word document ready for edit well before due date Received feedback from group members with ample time to edit	Did not realize that Gate 1 was to be graded only in wiki form and failed to communicate this to Communications Technology Expert in a timely fashion Issue was resolved and Gate 1 was formatted for and uploaded to wiki page on time
Project Manager and Intra-Group Communications Coordinator	Set timeline for work to be done, including internal group due dates for work leading up to class due dates Arrange group meetings, including coordinating group member availability and booking learning space in campus libraries as necessary Preside over group discussions and mediate group conflicts	Group members stayed on track to meet intra-group deadlines Group was able to have one formal and two informal meetings to work on Gate 1 Group was able to have two formal meetings to work on Gate 2 and connected informally several times before Gate was due No group conflicts arose that would require mediation	The change in TA office hours which currently no longer include Friday afternoons proved to be a setback for coordinating group times to meet in the product lab Resolution was achieved by requesting that the group be able to remove the impact wrench from the lab Another common time was established to do the dissection and hold future group meetings
Technical Expert: Communications Technology	Solid model components as necessary Manage wiki page Research any media which can be used and suggest additions to written materials as appropriate Organize and format any multimedia resources used by the group, including any video, photos and animation as needed.	Wiki page was formatted and uploaded on time for both Gates 1 and 2 Research was done regarding media to be used in Gate 2 and presented to group for discussion Wiki page was formatted and uploaded for Gate 2 with enough time for group input to be gathered, editing to be done and changes to be made to the page	Gate 1 proved to be very challenging due to time constraints – the group didn’t realize that Gate 1 was to be uploaded to the wiki page by the due date Gate 1 was submitted on time Challenges faced in formatting information to wiki pages have been overcome through learning more about using the wiki and greater consciousness among group members in formatting their respective contributions for easy transition into wiki format
Technical Experts: Dis-assembly Technicians	Research product for the purposes of dissection strategy Develop an order of operations and communicate plan to members before dissection Lead the dissection process by delegating tasks to members and making sure that procedure is followed	Ample research was done on product A clear outline of steps was brought to the dissection meeting	Minor challenges arose during the dissection which are detailed in Table 1.2: Assessment of the Project Management Plan

Table 1.2: Assessment of the Work Plan

Goals/Media Log	Successes	Challenges and Resolution
Casing Remove part of outside cover to provide cross-sectional view Take photos of cross-section	Back plate was removed without damaging any parts Photographs were taken and observations documented	Unable to take casing apart along its length to provide a cross-sectional view of parts from anvil to switch Started by removing back plate Parts gently fell out of housing after opening, making it difficult to figure out how it looked before it was disassembled completely Took a few extra minutes to document the order in which the parts came out and discuss how they could have fit together, physically piecing them together to see if group’s ideas were reasonable Previously listed tools (Allen wrench and screw driver) were insufficient to remove plate A punch was added to the rest of the necessary tools and a vice had to be used to hold the wrench while the punch was used to remove several pins in the housing and other parts of the wrench
Rotor, Hammer and Anvil Dissect rotor Take photos of rotor with system components and alone, both with fins intact and with fins separate Dissect hammer and anvil	All parts were examined and photographed, observations were documented Majority of learning experience occurred in this step – This was the first time dissecting a rotor in a pneumatic device for all members	Analysis of the hammer and anvil interface proved to be challenging A few extra minutes were taken to handle the hammer and anvil, using hands to recreate the motion of the rotor in an attempt to observe the motion created in parts within the hammer housing A general consensus was achieved among group members regarding the workings of this interface
Trigger and Valve Dissect valve and trigger mechanism Take photos of valve, trigger and small parts involved in air intake system and signaling devices	All steps and observations were documented, photographs were taken of all parts An examination of the parts of the valve revealed a response to a societal factor – a high level of noise output from the impact wrench was reduced by the use of the muffler	The casing for the valve appeared to be press fit or expanded inside the wrench After an attempt to remove the casing, the group left it intact, agreeing that it was probably not meant to be removed

Product Archaeology: Product Dissection

Step by Step Dissection of the Kobalt Pneumatic Impact Wrench

Difficulty Scale:

[1] Requires very little physical effort and/or very little mental comprehension

[2] Requires small amount of physical effort and/or a small amount of mental comprehension

[3] Requires some Physical effort and/or some mental Comprehension

[4] Requires a decent amount of Physical effort and/or mental comprehension

[5] Requires a lot of Physical exertion and/or mental exertion

Difficulties listed in bold at the end of each step.

Tools Required

1. Philips head screwdriver
2. Hammer
3. 5/32” Allen Wrench
4. 6/62” punch
5. 1/16” punch
6. 13/16” wrench
7. A vice (Not shown in diagram)

Removing/Dissecting the Trigger and Valves

Step 1

First, remove the Bushing (1) on the bottom of the gun where the air hose is attached and requires a 13/16” wrench. NOTE: the Bushing may be difficult to start to unscrew so a vice may be used to start it. Then remove the Plastic Plate and Screw (2) with the screwdriver. [3]

After those two are removed the inner parts should fall right out so care should be taken to not dump the contents. There are two parts that fall out and they are the Tipping Valve (3) and a Muffler (4). [1]

Step 2

Remove the Trigger (5A) by using the 6/62” Punch and hammer to slide out the Pin (5B) found next to the trigger in a little hole on the outside of the gun. The gun may need to be put in the vice to remove the pin. The Trigger (5A) will then pullout along with a spring in the trigger.[4]

Removing/Dissecting the Back cover of the Impact Gun

Step 1

Removing the Back Cover (6A) involves unscrewing the four Screws (6B) in the back with the 5/32” Allen Wrench.[2]

Step 2

Now the Back Cover (6A) needs to be separated into its components which require the cover to be clamped in a vice and the 1/16” punch and hammer are also needed. There is a small hole at the base of the Adjustment Lever (6C) where a Pin (6D) holds everything together. After using the punch and hammer to remove the pin simply pull apart the inner Adjustment Valve (6H) and the Adjustment Lever (6C).[5]

Step 3 After that a Cork Gasket (6F) Rubber Washer (6G) and a Rubber Ring (6E) can also come off easily. NOTE: Be careful of taking apart the adjustment lever because there is a small Set Pin (6J) and Spring (6I) for a clear stop at different adjustments. [3]

Removing the Rotor and Anvil for the Housing

Step 1

Now the Back Bearing (7) is visible in the back of the housing. NOTE: be careful not to flip housing over or all the inner workings of the gun will fall out. [2]

Remove the Back Bearing (7) and it will reveal the Rotor (8A) and Fins (8B).[1]

Step 2

Remove the Rotor (8A) and Fins (8B). The fins are not connected to anything and will fall out of the rotor when you pull it out. [1]

Step 3

Next remove the Outer Cylinder (9). It is not attached to anything but does fit fairly tight in the housing.[2]

Step 4

Next Remove the Front Bearing (10) by pulling it out.[2]

Step 5

Now the Anvil (11A) and Hammers (11B) can be seen in the front of the gun. To remove them place a hand over the back and flip the gun over. They should fall right out in your hand.[1]

Step 6

Now tip the whole Anvil and Hammer assembly up and the two Pins (11C) will fall out and then the Anvil (11A) will pull out allowing the Hammers (11B) to slide out and the only thing left is the Hammer Cover (11D).[2]

Fully Dissected View

You Now Have a Dissected Kobalt Pneumatic Impact Wrench

Parts Intent of Disassembly:

Every part discussed in this dissection guide is meant to be able to be taken apart. There are parts of the gun that are not taken apart in this guide and that is because they are not meant to be removed. The first of these parts are the bearing and bearing carriers that were just referred to as the back and front bearings in this guide but this part is actually a bearing that is press fit into a machined housing. This part is not meant to be taken apart because of it being press fit and the great difficulty and tooling to remove this press fit bearing from its carrier. The second part not removed in this dissection guide is a brass sleeve found in the valve hole of the housing. This was not removed because it is also press fit and is not meant to be removed for the same reason described earlier about press fit items.

Connection of Subsystems

To see what subsystems are connected and how they are connected please see diagram below:

There are different subsystems that are connected in different ways through the impact wrench. They all have separate functions that work together to perform the necessary function. They can be seen as follows:

Energy- This system is what allows the tool to function. It is powered by an air compressor so it is considered pneumatic. The compressed air or mass flow is what allows the internal parts, in this case the rotor and fins, to turn which allows for the rotor to turn and the hammers create the torque necessary to take off bolts.

Signal- The signal in this case is the trigger system. It is a type of control system allowing certain amounts of compressed air into the housing and the other systems. This is analog since a user’s finger is what pushes the trigger in and puts t where the user wants it.

Control Magnitude- This is the system that controls the maximum torque and direction that the tool is doing. This is controlled by a regulatory system which consists of a switch and plunger as the major components. This allows for an increase or decrease of compressed air allowed and also allows the air to go in specific directions for forward or reverse.

Internal Components- This is the system that converts energy from pneumatic to rotational. In this case from the energy system, the rotor turns allowing for the transfer to rotational energy and the hammer allow for the increase in torque. This is what allows the tool to take off and put on tight bolts.

The subsystems are connected the way that they are so that they can influence each other in doing their required actions. The system of valves to allow the compressed air flow in turn allows the rotor to turn and change the energy to mechanical energy to turn the anvil and hammers which in turn increase the torque while the bearings allow all the parts to turn smoothly. If these actions did not happen in this order then the toque that is created would not exists in as high of a form if not at all.

How the connections are implemented:

• Globally these systems are meant for areas that have the resources to be able to purchase and run an air compressor and power it.

• Societally these systems are set up for use in the US due to the fact that the tools needed to take it apart are in the English system.

• Economically these systems are made to be run cheaply due to the fact that it runs on air and the fact that the parts are made simply allowing easy mass production.

• Environmentally these systems are set up to leave no carbon footprint due to the fact that this run on air and that the majority of the parts are metal meaning that they can be recycled after its life is over.

Performance influences connection in this sense because if the torque was not needed then the anvil and hammers would not be necessary. The rotors working in turn with the anvil and hammers allows for the torque necessary to do its job.

The arrangement of subsystems is important due to the fact that without it the tool would not work. The energy comes into the system after being controlled by the trigger and regulators which in turn allows for that energy to be transferred into other energy. From that the energy is allowed to be able to turn bolts in the necessary directions.

• If certain systems were switched around unwanted interactions could occur. This can be seen if regulators were placed after the rotor and the hammers to regulate the speed and directions at the power point then problems could occur. It may work but reverse would be difficult in this set up.

• All the subsystems are placed where they are for a reason. Each part works in turn with each other for the final output. If specific parts are not together such as the rotor to the anvil and hammer working together to create high torque.

• Subsystems that cannot be adjacent are again the rotor, anvil, and hammers system. However, the trigger and valve system could be adjacent as long as the compressed air could come in and be regulated.