A rod or shaft {bearing, machine}| can turn in a sleeve full of oil. Lubricated-for-life bearings use a porous bronze sleeve soaked with oil and sealed to keep out dirt and prevent oil evaporation.
Two metal rollers {calender}| can squeeze together plies or texture coverings.
Pear-shaped rollers {cam}|, pushing on rods, can raise and lower rods.
A toothed wheel goes under can rim {can opener}|. Knife-edge or wheel cuts just next to top rim. Two arms squeeze knife-edge toward toothed wheel.
Cylindrical holders {carousel}| can rotate horizontally.
Tools can have a handle {crank, machine}| at one end and holder at other, to allow turning wheel.
Reels {fishing reel}| can have a spool for line, with a handle to turn spool and a guide to lay line down evenly on spool. A knob can let spool spin freely without turning handle or can brake and lock spool. Fishing reels {spinning reel} can have a fixed spool with axis pointing along rod toward fish. A guide {bail, fishing reel} on cup surrounding spool goes around spool, laying down line. Enclosed spools can have a hole in front.
Wheels can have an inner ridge {flange}|, to prevent wheel from falling off track.
Fasteners {hinge}| can rotate around an axis or pin {hinge pin}. Hinge sides {leaf, hinge} can attach on door or jamb outside surface {surface hinge} or on door or jamb edge {mortise hinge}. Hinge pin can insert into holes {knuckle, hinge}. Leaf with more knuckles is on hinge stationary part. Hinges {loose hinge} can allow one leaf to slide off pin of other leaf. Hinges {piano hinge} can have a permanent pin with two leaves that can meet parallel and flat.
To cut grass {lawn mower}|, hand lawn mowers {reel-type mower} have metal bar {cutting bar} at grass level and four helical reel blades, which scissor grass on cutting bar as reel turns with rolling wheels. Motorized mowers {rotary blade lawn mower} have two-blade propeller at ground level, which spins rapidly, sucks grass straight up, chops grass, and blows grass out. Slip clutch allows motor to keep spinning if blade becomes stuck. Motorized mowers start by pulling cord to spin motor crankshaft.
Wheels {ratchet wheel}| can have angled teeth, typically with pawl engaged in tooth, pressed down by spring. Oscillations in both directions turn into intermittent angular motion in one direction. If spring and pawl have higher temperature than rotor, ratchet tends to go backwards. Perhaps, muscle contraction involves linear ratchet effect.
Tools {sector tool}| can have two arms, with pivot at end, and be for numerical calculations, in same way as nomogram.
Rods {spit}| can hold an animal over coals to cook, and a handle can turn the rod.
Balances {torsion balance}| can use rods that twist.
Vanes {weather vane}| can point in direction from which wind comes, because force is greater on back-end larger surface.
Centrifugal pendulums {whirling regulator}| can control rotation speed in windmills.
Lathes can scrape wood {woodturning}|.
A ring holding a lower object, for example a ship's compass, can be in a base with two axes {gimbal}|, so ring stays horizontal when base tilts.
Spinning discs or circles {gyroscope}| {gyroscopic compass} can be in bearings {gimbal bearing} with three axes, which allow motion in any direction. Gyroscopes maintain space orientation. Laser beams can split and go through two paths, with different lengths if platform rotates, measured by wave interference. Paths are at triangle corners. Mechanical gyroscope rotation causes precession, which makes magnetic field. Semiconductor gyroscope vibrates in electric field against springs, and rotation changes vibration.
A rod has a spherical head and a joined rod has a hollow spherical receptor {ball and socket joint}|.
Two rods can hinge at obtuse angle {toggle joint}|, and rods have hinges at other end. Force at central hinge pushes far ends outward.
Two shafts can link at two axes {universal joint}|, perpendicular to each other and to shafts. Universal joint allows free movement in all directions.
Mechanical joints {caster, furniture}| {furniture caster} can allow swivel and roll.
structure
A shaft rotates around vertical axis. Shaft holds an axle around which wheel or sphere rotates. Wheel can swivel and roll freely, so furniture can move easily.
types
Bent tubes can hold both vertical shaft and wheel shaft {skew caster}. Balls can be set in vertical holders {ball caster}.
speed
Casters typically wobble at higher speeds.
brakes
Casters can have brakes. Pedals prevent roll but not swivel.
Objects {swivel}| can have a central sheath holding a post attached to a base, allowing horizontal object rotation.
Wheels {pulley}| on axes can have rope with which to lift loads by pulling down.
Two pulley sets {block and tackle}| can pass rope back and forth over wheels {block} {tackle, pulley}. Rope pulled long distance supplies force to raise load short distance.
Pulley middle wheels {idler wheel}| allow drive wheel and driven wheel to turn in same direction.
Tire tops can tilt {camber}| out or in, rather than be vertical.
amount
Camber ranges from -1.0 to +1 degrees. Negative camber tilts in. Positive camber tilts out. Positive camber allows better support by wheel bearings.
turn
Tires tend to tilt out toward outside turn, because tread sticks to road and tire top has centrifugal force.
When car body slides toward outside turn, MacPherson strut suspensions tilt tires out, but unequal A-arms tilt tires in. During turns, tire inside or outside can lift off road. Negative camber for MacPherson strut suspensions and positive camber for unequal A-arms allow tires to be vertical during turns, when traction is most important.
pull
If one tire has higher camber, car pulls to that side.
road
Because road crown pulls car to right, in right-hand-drive countries, left tire can require higher camber.
Tires can lean to front or rear {caster, tire}, rather than be vertical. Positive caster is forward tilt. Too much positive caster causes shimmy, because weight falls in front of tread. Too little positive caster causes poor tracking, because weight falls down tire center.
Caster settings typically are 0.5 to 4 degrees. From 3 to 4 results in better straight-line tracking but heavier steering. From 0.5 to 1 makes lighter steering, but poorer straight-line tracking.
Negative caster is backward tilt. Negative caster puts weight behind tire and causes unstable tracking, because it pushes tire forward in various directions.
Tires can swivel left or right, rather than aligning straight-ahead {toe}|. Toe is in or out. It causes stability because, during turns or bumps, tires tend to return to straight-ahead position. At higher speeds, toe becomes slightly more out, so starting slightly in is better. Out is only for front tire center offset or special wheel bearings. Rear tires are neither in nor out, because in or out causes instability and rapid tire wear.
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Date Modified: 2022.0225