Proces saw Chain
SDES-502 Prof. John Schaffeld 02/15/2012 - 03/11/2012
Chen Lu & Yi Liu
To design a chainsaw in ergonomic and safety perspective
02/15/2012-
02/23/2012
Research & Analysis
02/24/2012-
02/29/2012
Conception
03/01/2012-
03/06/2012
Usability Test
03/07/2012-
03/11/2012
Final design
And process book
Research
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Professional user
How to use a chainsaw?
Home user
Professional user
Felling Felling is the process of downing individual trees, an element of the task of logging.
limbing An extension or projecting part of a tree. When the tree is lying on the ground, branches may be storing enormous potential energy through mechanical strain. When a branch is cut, often with a chain saw, this energy can be released suddenly and the branch can jump dangerously. In addition, a branch may be supporting the tree, and the tree can fall or roll when the branch is cut. For these reasons, delimbing is a skilled operation requiring careful safety planning.
Bucking Bucking means cutting felled trees into short logs.
Home user
Cutting branches and woods
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Safety
Kick back Muscle presure White fingers Safe cutting Carpal tunnel syndrome Hearing Damage Respiratory problem
Kick back Kickback may occur when the moving saw chain near the upper quadrant of the bar nose contacts a solid object or is pinched.
Muscle presure Long period using with chainsaw may cause crucial presure on elbow and front arms area. The presure will cause serious medical issues very badly.
White fingers Vibration White Finger (VWF) is a Repetitive Stressful Injury also known as Hand-Arm Vibration Syndrome (HAVS). The injury results from the continuous use of vibrating hand machinery for prolonged periods without sufficient breaks.
Safe cutting Keep your body out of the path of a potential kickback. When making any vertical (bucking) cut, keep your body to the left of the guide bar, out of the plane of chain rotation.
Carpal tunnel syndrome Carpal Tunnel Syndrome (CTS) is an entrapment median neuropathy, causing paresthesia, pain, numbness, and other symptoms in the distribution of the median nerve due to its compression at the wrist in the carpal tunnel.
Hearing Damage The chainsaw noise can cause hearing problem or even deafness. Power tools can cause hearing damage after only 30 seconds.
Respiratory problem The toxic gas and dust from chainsaw may cause Respiratory problem
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Existing products
Other brands
Analysis
We asked a lot of people try to hold the old chainsaw for a while until they can not stand the weight. Most of them can only hold the chainsaw for about 2 - 3 minutes. Chainsaw is heavy. They all feel crucial presure, especially from their left forearm muscle.
Muscle presure analysis Biggest pressure goes to bicep and extensor carpi radialis longus of left arm. Since continuly squeezing rear handle with right hand, the hand muscle will sour.
We measured main dimensions of existing chainsaw to help us design our own chainsaw. Handle is the focual point of our observation. We also learned how a chainsaw is combined with different parts.
The elements of chainsaw
Conception
Evaluation 1 Develop feasiable ideas from sketches
Usability Test
Mock Ups
Use foam to build previous designs for usability test
We built two main bodies and four handles to find out the best combination.
A1
A2
A3
A4
B1
B2
B3
B4
Evaluation 2
Ask different people try our new designed chainsaw mock ups
TESTERS USED IT BEFORE?
BEST CHOICE
COMMENTS
A4
If I can hold both upper and lower parts of handle 1, it would be better.
A1
Traditional one feels better. Handle 2 is really bad, I can not use it.
B1
The movable part is not stable for power tool like chainsaw.
A4
If I can hold three sides of handle 4, it would be better.
A4
Handle 4 gives me a lot of flexibility. Based on this result, we decided to develop A1 as our final design.
A1
Movable parts cost too much to produce.
A4
I love A4 a lot. I hate handle 2, it disturb me a lot when I try to use it.
A1
There are reasons for original chainsaw to be like that.
A1
I like traditional one. Handle 2 is bad.
B1
The traditional handle allows users to cut in straight way natually. Hanlde 4 can be used by home users not professional users. I can use handle 1 to cut in low position without blocks.
Final design
Rotatable handle can fit with both professional users and home users. Change the handle to an angle to cut in low position without any blocks. Cutting logs straightly with straight position-handle as tradition way.
Reference:
How towork with a chainsaw
http://www.jackssmallengines.com/pdf/chainsaw_cons.pdf
Chainsaws at work
http://www.hse.gov.uk/pubns/indg317.pdf
Tophandled chainsaws
http://www.hse.gov.uk/pubns/afag308.pdf
Basic chainsaw felling and manual takedown http://www.hse.gov.uk/pubns/afag302.pdf
Tree work
http://www.hse.gov.uk/pubns/indg278.pdf
Chainsaw felling of large trees
http://www.hse.gov.uk/pubns/afag307.pdf
Chain Saw Safety
http://www.uscupstate.edu/uploadedFiles/About_upstate/Planning_and_Organizational_Development/ Training/Chain%20Saw%20Safety.pdf
Chain Saw Safety Manual
http://www.stihl.co.nz/p/media/download/uk-en/STIHL_Chain_Saw_Safety_Manual.pdf
How to Operate Chain Saws Safely
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cts=1331520388821&ved=0CEQQ FjAA&url=http%3A%2F%2Fwww.flagsafe.ufl.edu%2Fpowerpoint%2Fchainsaw%2520safety%25203.ppt&ei= gmNdT9LsPJCatwfiy5CADw&usg=AFQjCNHgQXx1Et8CfqezTPSWu5DaZlbONg
Chain Saw Injury Statistics http://www.elvex.com/facts08.htm
Chain Saw Safety
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=18&cts=1331520660575&ved=0CGw QFjAHOAo&url=http%3A%2F%2Fwisha-training.lni.wa.gov%2Ftraining%2Fpresentations%2FChainsawSaf ety.pps&ei=jGRdT-rfBc_qtgfu7_mGDA&usg=AFQjCNGkw7dSk1Mt365yffzvX0xpOYTWWA
Sites:
http://en.wikipedia.org/wiki/Chainsaw http://www.stihl.com/ http://www.husqvarna.com/us/products/chainsaws/husqvarna-chainsaws-for-homeowners/ http://www.hse.gov.uk/treework/safety-topics/chainsaw-operator.htm http://www.youtube.com/results?search_query=chainsaw&oq=chainsaw&aq=f&aqi=g10&aql=&gs_ sm=3&gs_upl=147l693l0l841l6l6l0l1l1l1l228l530l3.1.1l5l0 http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=chainsaw&x=0&y=0
sa roces
Chain
Chen Lu & Yi Liu SDES-502 Prof. John Schaffeld 02/15/2012 - 03/11/2012