Ergonomics
SCADpro x Snap-On | Fall 2020
Researched
Oxo Good Grips: User Experience
"They want products that look and feel good, and crucially, that don’t make them feel labelled as disabled or different."
Helen Hurman, Arthritis Research UK
“The satisfaction they had was like a lightbulb went off and they could do something … The product itself really is never that important. What someone can accomplish, that’s important. It’s how it makes them feel.”
Davin Stowell, Smart Design
Oxo Good Grips: Human Factors Research
Oxo Good Grips: Human Factors Research
How wide is the average palm?
What size works for everyone?
How do unique cultural factors affect design requirements?
What works and doesn’t work about the current iteration?
What do people think about the product? What do they like/dislike?
What can we learn from all of our research? Which designs provide max value?
Rapid Wheel Removal
When it’s used: Mid race, training rides. By mechanic and cyclist.
Body position: bend over
Typical handling: 2 hands
Pain Points: thru axle threading often misses. Different people tighten more or less than others. Back wheel is hard to very quickly change. Derailleur, chain and cassette get in the way. Disc brakes can close and can be difficult to insert the rotor into if in a rush.
Current design advantages: Some do not require an allen key
Plug in: The most basic thru axle. Use an allen key to tighten to frame.
Modified plug in: a removable handle allows the bike to be lighter and more aerodynamic.
Modified plug in: The handle is similar to the quick release design and allows the user to tighten it without an additional tool.
Proprietary design: This RAT thru axle is meant to be a fast change option. However, users have found little difference in changing time.
Tire Replacement/
Tire Lever
When it’s used: Flats on training rides. Replacing an old tire. Mechanics and cyclists. Never during a race.
Body position: Bend over.
Typical handling: Hands, finders, arms, legs.
Pain Points: Hurts hands, can break easily, not ergonomic
Current design advantages: Cheap, easy to use, universal application
Current design disadvantages: body and wheel positioning are awkward. Difficult to place some tires. Can puncture tube when using to reseat tire on wheel.
Tire Replacement/
Tire Lever cont.
Form: Made with sharp corners & is thin, typically geometric & blocky,
Comfort: huge opportunity for ergonomics, overmolded grips & rounded edges at minimum, often pushing on sharp & thin edge with thumb
Pain Points: putting tire back on is more difficult, slips in hand/off of wheel rim, awkward to hold wheel while changing tire, lever can break
Process: Many time-consuming single steps
Torque wrench
When it’s used: Mostly by mechanics. Some cyclists doing at-home repairs. Usually used during tune ups, bike builds, and part replacement. See link in notes for more from Park Tool.
Body position: Standing, crouched, bent, squat depending on bike part.
Typical handling: one hand.
Pain Points: Different torque specs throughout bike. Lots of torque wrenches needed.
Current design advantages: Prevents over tightening and breaking your bike. This is SUPER important. You don’t want to break a $1k+ part because of a slight over torque (I’ve done it. Baaaaad news)
Current design disadvantages: You need multiple wrenches or inserts. You need to know the specs on all of the parts on a bike to make sure you tighten everything properly.
Torque wrench cont.
Paint Points: Hard to read numbers on tool (clearly identifiable), need to know specific specs
Key Points: Needs to fit into tight spaces, handle should be in appropriate position not to hit pieces of bike/inhibit performance
Spoke wrench
When it’s used: when wheel is not true. When you need to replace spoke. When you bend a spoke. When you are putting a new nipple on. Building a wheel. Mostly mechanic. Some cyclists carry on training rides.
Body position: Usually standing at a wheel truing stand.
Typical handling: hands and fingers
Pain Points: Small. Highly specialized knowledge needed.
Current design advantages: Simple design. Necessary to keep wheels straight.
Current design disadvantages: There are a variety of spokes and nipples. Difficult to true a wheel without a wheel stand.
Spoke wrench
Pain points: awkward to hold, small size is hard to grab & maneuver, need to fit fingers around tool and spokes
Key points: Need to fit fingers around tools and spokes, specialized knowledge needed to use tool, not taken on road, should fit multiple hand sizes
CO2 Inflator
When it’s used: Only on training rides. Never races. Only cyclist, not mechanic.
Body position: Bent over
Typical handling: 2 hands, fingers.
Pain Points: Small thread on canister. Takes up space. Canister becomes very cold. Can bend tube valve. Can accidentally deflate tire. Break easily.
Current design advantages: Rapid tire inflation, compact compared to a pump
Fun and different way to carry your CO2 and inflator. Hidden in bottom bracket
CO2 Inflator cont.
Issues: cold can burn skin, difficulty placing cartridge on wheel straight
Strains: fingers, middle, ring, & pinky fingers flexed to keep hold of inflator while avoiding cold canister
After inflation: CO2 can pass through valve stem & rubber, so tire can end up flat again within 24 hours, short term fix
Small & simple is good
Multi-tool
When it’s used: On training rides or in the shop. By mechanic or cyclist depending on tools included.
Body position: bend, squat, standing. Depends on part of the bike that needs work.
Typical handling: Hands. May have legs or back bent.
Pain Points: Hand strength, tool options, compact size, should fit in pocket or saddle bag.
Current design advantages: There are numerous options
Current design disadvantages: There is no “ideal” combo. Small size may make tools impractical
Multi-tool cont.
Key points: Small & awkward, tools can become impractical if not in right size or setup (making multi-tool useless)
Movement: modularity brings unwanted movement, not enough strength
Features: Lightweight, compact, work in tight spaces
Pain Points: Hand strength, tool options, compact size, should fit in pocket or saddle bag.
Current design advantages: There are numerous options
Current design disadvantages: There is no “ideal” combo. Small size may make tools impractical
Tool bag
When it’s used: Only the mechanic. On travel for races. Never the cyclist.
Body position: Backpack, cross shoulder, duffle, etc.
Typical handling: hands, back, arms, small car,
Pain Points: Must be under 50lb, must be easy and fast to access.
Current design advantages: N/A
Current design disadvantages: limited options, heavy, mechanics usually create their own.
Tool bag cont.
Body fit: backpack is most comfortable to carry, manage even distribution of weight
Organization: structure can be good, sides of bag can fall over, people prefer general pockets/spaces over specific assigned spaces for tools
Eyesight/sorting: Easy to see all tools, clearly organized, can be dark inside bag (bring bright color, light)
Saddle bag
When it’s used: by the cyclist, only on training rides. Never the mechanic.
Body position: N/A
Typical handling: Zipped, velcro, seat rail attachment.
Pain Points: Size, Ease of closing
Current design advantages: numerous options
Current design disadvantages: Can fall off a bike, may not fit everything you need
Wrist movement
Extension: 60-75 degrees
Flexion: 60-80 degrees
Radial Deviation: 20-25 degrees
Ulnar Deviation : 30-40 degrees
Rotation: 70-85 degrees / 80 degrees
Arm Movement
Abduction: 180 degrees
Adduction: 45 degrees
Horizontal Flexion: 130 degrees
Horizontal Extension: 45 degrees
Vertical Flexion: 180
Vertical Extension: 60
Weight
Ideally, a worker should be able to operate a tool with one hand. The weight of the tool may depend on the use:
It is also important that the centre of gravity be aligned with the centre of the gripping hand. In other words, tools should feel "easy" to hold either in an upright position or in the position it will be used.
The crucial ergonomic principle in tool use and design -- bend the tool, not the wrists
Diameter
Handle diameter recommendations vary.
In general, cylindrical handles at 40mm (1.5 in) offer a better power grip, with a range from 30-50mm (1.25 to 2 in).
For precision grips, a diameter of 12mm (0.45 in) is recommended, with a range of 8-16mm (0.3 to 0.6 in).
The larger diameter will allow for maximum torque, while the smaller diameter helps with dexterity and speed.
Length
A handle that is too short can cause unnecessary compression in the middle of the palm.
It should extend across the entire breadth of the palm.
Tool handles should be not less than 100 mm (4 in) to reduce the negative effects of any compression exerted.
Handles around 120 mm (5 in) are generally recommended.
Keep in mind that the use of gloves requires longer tool handles.
Separation between handles
Crushing, gripping or cutting tools such as pliers or tongs are equipped with two handles.
The recommended distance separating the handles is between 65-90 mm (2.5 to 3.5 in).
Grips that are larger than 100 mm (4 in) will be difficult for some users.
Tools with larger or smaller spans will reduce one's maximum grip strength.
Material and texture
To ensure a good grip on a handle, sufficient friction must exist between the hand and the handle.
This is particularly important where a considerable force must be applied with a sweaty hand.
Hand tools should be made of non-slip, non-conductive and compressible materials.
For example, textured rubber handles provide a good grip, reduce the effort needed to use the tool effectively, and prevent the tool from slipping out of the hand.
Power tools
Frequent movements of the index finger while operating the trigger of power tools (such as a power drill) poses a considerable risk for both "trigger finger" and "trigger thumb" (tendonitis in the index finger and/or thumb).
A longer trigger which allows the use of two or three fingers to activate them reduces discomfort and minimizes the risk for injury.
"Anti-vibration" materials will dampen some vibration above certain frequencies that are characteristic for the kind of material used.
HANDLES
Ergonomically design hand tools feature materials designed to increase grip. This means that the operator aligns their fingers in a manner where they work in conjunction with each other to maximize the hand capacity.
Shape
The shape of the handle affects wrist and arm posture. The handle shape varies according to the task each tool has to perform. Taken into account are also the orientation and layout of the task as well as the workplace and its existing conditions. It is important to select a handle that will, with the specific said tool, will not require wrist flexion, extension or ulnar/radial deviation, in order to allow the user to maintain a neutral wrist posture.
Depending on how the force is exerted, the handle’s angle will vary. When the force is applied horizontally, a pistol grip is most suitable. When the force is exerted perpendicular to the straightened forearm and wrist, in other words when the force is applied vertically, it is best to use a straight handle. A task performed in the same plane and height as the arm and hand calls for a bent handle.
SPAN
Double handle tools such as tongs and pliers used for crushing, cutting and gripping require a handle spam of 3 inches, with a minimum of 2 inches and a maximum of 4 inches. Tools with shorter or greater span reducer the user’s maximum grip strength.
What to avoid
"Bend" the tool, not the wrist; use tools with angled or "bent" handles, when appropriate.
Avoid high contact forces and static loading
Reduce excessive gripping force or pressure.
Avoid extreme and awkward joint positions.
Avoid twisting hand and wrist motion by using power tools rather than hand tools.
Avoid repetitive finger movements, or at least reduce their number.
Avoid or limit vibration.
Minimize the amount of force needed to activate trigger devices on power tools.
Picture dump
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