Nerf-N-Stike Product Explanation

Revision as of 16:26, 30 November 2012

Purpose

This gate encompasses a detailed product explanation of the Nerf-N-Strike Elite Hail Fire. The purpose of this gate was to reassemble the Nerf-N-Strike Elite Hail-fire and analyze all the information that was gathered to make detailed conclusions about the product. This gate was examined on the component and system levels in the following areas:

1. Project Management: Critical Project Review
   • Cause for Corrective Action
2. Product Archeology: Product Explanation
   • Product Reassembly
   • Mechanisms
   • Design Revisions

Project Management: Critical Project Review
This section provides an overall assessment of our work and management plans for gate 4. In terms of analysis we discussed our management plans; including how they have worked out thus far and identified potential and past challenges that existed within the overall group from a management perspective and how discussed how they were dealt with.


Product Archeology
This section provides an overall product explanation. The product explanation looked at Product Reassembly, Mechanisms and Deign Revisions.

• Product Reassembly:The product reassembly includes a step-by-step process describing the assembly process for the Nerf-N-Strike Elite Hail Fire. The process was rated on a difficulty scale determined by the group and includes information on the tools used and how they were used to help an individual not familiar with the product to successfully reassemble the product. Relevant pictures where included for visual understanding.
  
• Mechanisms: This section identifies two mechanisms our device used to generate motion, control system behavior, and modify/condition energy; the trigger motion and the magazine rack rotation mechanism. These mechanisms are further explored in its purpose, how it works and equations required for the design of the mechanism.
  
• Design Revisions:This section includes three design change recommendations for the product at the system level. These design revisions address; global, societal, economic and environmental concerns. The changes improve performance, serviceability and cost.

Project Management: Critical Project Review

Cause for Corrective Action

Work Plans
In terms of our work plans we have taken special consideration to make sure each deadline is met as outlined in the Work Management Project Timeline. Having deadlines for specified portions of the overall gate has helped break down the workload into manageable sizes for the group to complete in a timely manner. Each portion of the work is then collected and then combined into a cohesive product. Once the draft is complete the group then sets aside a few days for the final revisions and Wiki formatting which includes tables, diagrams and pictures. We did have some problems with interpreting some of the criteria that was graded. Much of the graded criteria were implicitly stated, but some of the criteria that we needed to interpret, we were unable to properly meet the requirements of this non-implicit criteria. We struggled with this because we viewed the assignment with a more straightforward approach and in doing so we neglected to address some aspects of our assignment that we should have. In order to fix this problem we had we will go more in depth in our reasoning behind our answers as well as work to more thoroughly decipher the non-implicit criteria from what information and questions we are presented with.

Management Plans
Management for the group has worked well up to this point. In the beginning there was an issue with time management which was a minor challenge for the group however after addressing the issue to the entire group we were able to work together to come up with solutions and increase communication to handle issues regarding time management. We now have more group meetings and more clearly establish tasks for group members to complete. We have grown as a big loving family with one another, communicating outside of the class project which has helped strengthened our relationship and cohesiveness as a group. This process has helped contribute to the overall success in completing our gate 3 more efficiently. The communications liaison plays a crucial role is disseminating information and keeping everyone on the same page. Respect for each group member has definitely been a significant assistance to the overall work ethic and production level of each group member; we all want to see each other excel which perpetuates into the overall success of our group. We all strive to attend all meetings and accomplish the tasks we establish for that given group meeting. We also make sure we set group meeting times in which all members are able to be present. If there is ever a case where an additional meeting is necessary we work to meet again. This has been quite easy due to the fact that everyone is open and willing to set time aside to finish the necessary tasks.

Product Archeology: Product Explanation

Product Reassembly

Assembly Difficulty Each step of this assembly process entails a certain level of difficulty in its successful completion. Therefore a system in which each step’s difficulty is labeled provides helpful added assembly information for the person executing the assembly. The first criteria for establishing our difficulty rating system is time necessary for step completion. The second criteria for establishing our difficulty rating system is step complexity. Step complexity is defined by the number of parts involved to complete the step. If there is a situation where a given step meets the time qualification of one difficulty rating and the complexity qualification of another difficulty rating then the higher rating will be used. The specific difficulty ratings are outlined below:

Difficulty Rating 1: Step requires time of less than one minute. Step requires assembly of 2 or fewer parts.
Difficulty Rating 2: Step requires time ranging between one and five minutes. Step requires assembly of 3-5 parts.
Difficulty Rating 3: Step requires time in excess of 5 minutes. Step requires assembly of more than 5 parts.

Steps	Components Assembled	Tools Used	Figures	Difficulty Level
1	Place the magazine pushrod spring on its fixture in the external frame and attach it to the magazine pushrod as seen in Figure 1. Make sure these connections are secure.	Hands	Figure 1: Click picture to enlarge	2
2	Place the right half of the electronic motor case in the barrel of the gun as seen in Figure 2	By hand	Figure 2: Click picture to enlarge	1
3	Place the muzzle at the front of the electronic motor case and the dart intake duct at the back of the electronic motor case. Then place the electronic motor assembly vertically over these two components in the barrel of the gun as seen in Figure 3	Use Hands	Figure 3: Click picture to enlarge	2
4	Place the left half of the electronic motor case over the electronic motor assembly and then screw the electronic motor case Phillips head screw into the connected electronic motor casing to connect the case to the frame as seen in Figure 4	By Hand and Phillips head screw driver	Figure 4: Click picture to enlarge	2
5	Place the magazine rotation handle base into the two according holes in the barrel of the gun and the magazine pushrod as seen in Figure 4	Use Hands	Figure 4: Click picture to enlarge	1
6	Place the magazine rack in the center of the gun and connect it to the magazine pushrod with the magazine pushrod screw as seen in Figure 5	Use hands and Phillips head screw driver	Figure 5: Click picture to enlarge	2
7	Place the trigger assembly in the handle of the external frame over as seen in Figure 6.	By Hand	Figure 6: Click picture to enlarge	1
8	Slide the viewing window on to the trigger mechanism and situate it above the magazine the rack as seen in Figure 7	By Hand	Figure 7: Click picture to enlarge	1
9	Place the battery tray above the trigger mechanism as seen in Figure 8	By Hand	Figure 8: Click picture to enlarge	1
10	Place the other half of the frame on the half containing the internal parts and use the Phillips head screws to connect the two halves of the frame as seen in Figure 9	Phillips-head screwdriver	Figure 9: Click picture to enlarge	3
11	Place the magazine rack covers into their designated slots as seen in Figure 10	By Hand	Figure 10: Click picture to enlarge	1
12	Place 6 darts into each of the magazines as seen in Figure 11	By Hand	Figure 11: Click picture to enlarge	1
13	Place the loaded magazines into any of the slots on the magazine rack as seen in Figure 12	Use hands	Figure 12: Click picture to enlarge	2
14	Place the magazine rotation handle on the ends of the magazine rotation handle base as seen in Figure 13	UseHands	Figure 13: Click picture to enlarge	1

Note: The assembly is not the same as the disassembly because there were steps in the assembly that were not in the disassembly. This occurred because when in the product disassembly opening the frame and removing some components causes other components to fall out meaning there removal would not be recorded in the dissection, but would be recorded in the assembly.

Original Assembly

In the original assembly of the Nerf N-Strike Hail Fire Elite they went through the same steps as we did in our reassembly of the product after our dissection. We did all of these processes through the use of our hands and Phillips head screw drivers. Nerf uses an assembly line of people operating and maintaining machinery. They implement the use of machines to quickly and efficiently mass produce this product.

Mechanisms

• Trigger Mechanism
  

Mechanism Type: Rack and Pinion
Mechanism Purpose: The rack and pinion design of the trigger mechanism allows the energy from the user pulling the trigger to be transferred to the rack, which pushes the part into the electric motors and fired out of the gun. When the user pulls the trigger they are actually moving a rack towards the rear of the gun. This rack gear is on the bottom of the pinion gear and there is another rack gear on the top of the pinion gear, which moves towards the front of the gun and pushes the dart into the electric motors when the trigger is pulled.
Equations:

1. T – rpF = Ipθ
   
2. F = mx
   

T- Input torque
rp- Pitch radius of pinion
F- Reaction force of the contact point
Ip- Rotational inertia of the pinion
θ- Rotation angle (in radians) of the pinion
x- Displacement of the rack

• Magazine Rack Rotation Mechanism
  

Mechanism Type: Crank Slider
Mechanism Purpose: The crank slider design of the magazine rack rotation mechanism allows the energy from the user pulling the rotation handle to be transferred to the crank, which rotates. This rotation of the crank pushes the rod that is attached to the crank, which rotates the magazine rack. The mechanism is then returned to its original position by the return spring at the front of the gun.
Equations:

1. x = R [ 1 – cosθ + n (1 - √(1 – (sinθ/n)2)), where n = L/R
   

x- Displacement of the rod
R- Radius of the crank
θ- Crank angle
L- Length of the rod

Design Revisions

Revision 1:
Move the magazine rotation handle to the side of the gun rather than the top of the gun. One of the problems with the current location of the rotation handle is that it gives no ability for there to be any attachments mounted on the top of the gun, such as a mounted scope to help increase accuracy. This could be achieved by taking off the handle on the top and then extending the base of the handle so it is protruding out of the side of the gun while still being able to be pulled back allowing for it to maintain its function. This change would be a global factor because with the handle located on the top it gives the gun an unrealistic feel and look which could become a problem when selling the product considering consumers are more likely to buy a Nerf gun that is more comparable to those that are used in the military. Also, having your supporting hand located either on the side or bottom of the gun allows for a steadier shot. This in turn also makes it an economic factor because if the product sells more because of its more realistic look then the company will benefit. It could also be economic because they would sell more additional attachments such as scopes.

Revision 2:
Make the gun automatic rather than semi-automatic. This would increase the performance of the gun greatly because you would have a higher rate of fire. You could achieve this by switching out the rack and pinion system currently used in the gun and putting in a cams system instead. Another thing you would need to add is another electric motor in the back of the gun to operate the cams system. This would cause an increase in the necessary amount of battery power. This change would possibly cause the need for the gun to use C or D batteries rather than AA batteries. Another effect of this change would be the need for the gun to hold more ammunition because with an increased fire rate you would run out of darts quicker. One way this could be fixed is by adding more magazine slots in the magazine rack. This revision is a global factor because with the technological advancements over the years, customers want the product to be as current as possible and having the gun be fully automatic is the most advanced feature when it comes to the firing mechanism. This again makes it an economic factor because even though it would cost more to make, with these new revisions it could be sold for more and the fully automatic firing feature is a strong selling point.

Revision 3:
Input a rechargeable batter system rather than the 4 AA battery system. One problem with not having a rechargeable battery is that you need to constantly change batteries every time they run out, while with a rechargeable battery as long as you have it charging when you’re not using it, it will never run out of power. The obvious first step in making this change is to have the gun come with rechargeable batteries rather than just an empty battery tray. The next thing that would be needed is a recharging station for when the gun is not in use or is out of battery. This is an environmental factor because it reduces the amount of batteries that need to be made and more importantly, thrown away. This is also an economic factor because customers are more likely to buy something that won’t constantly need batteries purchased for it. It can become even more cost beneficial because even though they are rechargeable, the battery’s capacity does decrease over time, so if Nerf was the only company with replacement rechargeable batteries for their products then they could have another product to enhance profits.

References

[1] All other information was generated from group members and information gained from previous knowledge