Staple gun
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Contents |
Group 3
- Kristine Falletta
- Kacy Hess
- Galen Mullins
- Josh Schmieder
Product Analysis
Function/Purpose
The function of the product is to fasten materials together using staples. This product is meant to be used to hang items from surfaces (such as walls, ceilings, etc.), attach one item to another, and other similar actions. It can also be used to shoot staples at targets, though this is not an intended use.
Inputs/Outputs
In order to use the staple gun both a force and a material are needed. The staples must be properly loaded in the gun, after which the proper force must be applied to the handle (generally created by the squeezing of a hand). This results in a staple projectile (typically into a surface) and recoil from the handle.
Typical Use Scenario
We asked a typical user to try to use our product and documented the steps he took while attaching a piece of wood to a corkboard.
1. Picked up the staple gun and placed hand on handle
2. Positioned material (wood) with empty hand against item to be fastened to (corkboard)
3. Positioned gun against the wood
4. Squeezed handled to release staple
5. Removed gun and checked to see if the materials were fastened together
6. No staple was present so repeated steps 2-5
7. When no staple was present again, located reloading place for staples to check for staples
8. Removed slider on bottom of gun and check for staples
9. When no staples were present, found staples and attempted to insert them
10. Positioned staples over extruded part of staple loader and tried to close the gun
11. When the slider did not close, repositioned staples inside gun and closed slider successfully
12. Repeated steps 2-5
13. Found that staple had successfully attached the two materials
Note: May have to unlock staple gun or adjust staple power before use. Do not always have to insert new staples.
Intended Use/Limitations/Annoyances
As previously stated, the intended function of this product is to fasten materials together by shooting a staple through them. Other features that are used to enhance this function include the ability to lock the handle for more compact storage and/or safety reasons, adjustable power so that the user may staple with more or less force, as well as a loading mechanism. Staples may be loaded by sliding the bottom of the stapler out, inserting the staples into the open compartment, then sliding and locking the bottom of the stapler back in place. There are a number of limitations and annoyances with this design. With regards to typical use, a great amount of force is required to squeeze the handle for shooting staples. It is exceptionally difficult to exert enough force to release a staple when one is stretched out over and long distance and trying to press against a surface at the same time. This is true even if the staple gun is on the low power, which, as it turns out, is difficult to adjust. It is nearly impossible to reach into small or tight places due to the size of and configuration of the staple gun. Safety and storage are also of concern. There is no safety lock currently installed on the staple gun. (Note: the lock that is already on the stapler is intended for storage purposes, and does not prevent the accidental trigger of the staple gun.) Also, the size is awkward and difficult to store or carry on your person when also using other tools. Some of the advantages of this design are its sturdiness and solid weight, the easy loading mechanism (once the process is known), the comfortable grip, and the availability of a power adjustment option (which also makes the product seem higher in quality/more advanced).
Different Users / Use Scenarios
There are some instances that may occur in which the user might find this product difficult to use. Should the force to dispense staples be too high, people with small or weak hands would not be able to use it. On the other end of the spectrum, people with large hands may not be able to fit their hands in the handle. Another scenerio that could occur is the desire to use the staple gun improperly (e.g. shooting staples at one another). Finally, people who need to fit staples in small, tight places may not be able to get the gun into those places.
Other Stakeholders
Identify other stakeholders besides the end user, such as those who manufacture, distribute, sell, purchase, assist, install, maintain, repair and manage the product's end of life. Document attributes of the product that affect these stakeholders.
Product Dissection
How it works
The following is a link to a video of how the staple gun works: http://picasaweb.google.com/kfalletta/StapleGun12407/photo#5025415866390932786
This staple gun is made to work in a very simple manner. The user inputs a force by pushing down on the handle. This in turn, lifts up the loader which has two hooks that pull up on the two tension bars. The lower tension bar lifts up the staple pistion as it rises. When the tension bars are bent back far enough they slip off the hooks on the loader and snap downwards forcing the staple pistion into the next staple sitting in the queue. As the handle is released by the user, the reloader springs push the loader down and, because of the curved edges on the hooks of the loader, the loader hooks itself over the tension bars again and is ready to use again.
Detailed function of parts
(Josh fill in this section. You might want to try to blow up a picture of all the parts in the gun and label them and talk about what they do. Just a thought.) Procedure with pictures coming soon. Preview: http://picasaweb.google.com/kfalletta/StapleGun12407
Documentation
Parts List
* Disclaimer: Materials and Manufacturing Processes are not within our area of expertise. Therefore, all materials and processes are our best educated guesses based on our knowledge and research.
Design Considerations
Design for 'X'
Design for Assembly
- ridges in chassis
- tapered screw guides in chassis to ensure alignment
- parts fit together instead of having to be screwed together
Design for Disassembly
- designed so that this product can not be easily disassembled by the user
- hex bolts with circular protrusion in the middle require special tools
Design for Environment
- materials aren't biodegradable, but they aren't toxic (environmentally neutral)
- aluminum = recyclable
Design for Manufacture
- two bars -> easier to stamp these two thin bars rather than one thick one
- parts can be manufactured with relatively simple, common, and straightforward processes
- most parts are made by injection molding or stamping
Design for Reliability
- an extravagant amount of grease (waterproof?)
- parts are sturdy (ie, can drop without consequences)
- ratio of force to yield stress is minimal
- rust proof: parts are made out of aluminum, stainless steel, and plastic
- user can't easily open the product, so parts are less likely to be fiddled with
Design for Safety
- user can't disassemble very easily
- if you do disassemble the product, no parts will fly out at you or cause hazards
- staple gun is slightly difficult to shoot, thus, gun will not randomly fire
Design for Usability
- plastic grips for comfort
- intuitive (point and sqeeze)
- flaw: staple loading process is slightly counter-intuitive (despite advertising)
- loading process is very easy once the user knows how
- power adjuster
- staple comes out at the top end of the gun - a very intuitive and convenient location
Failure Mode Event Analysis (FMEA)
- staple jams? -> tested gun with one staple
- breaking? -> dropped staple gun
- water damage?
- broken/degraded springs? -> tried gun without springs