Transcript Mechanical Fasteners - California University of PA

Basic
Mechanical Fasteners
TED126
mechanical fasteners…Choosing
The choice of a fastener is dependent
– on the design requirements and the
– environment in which the fastener will be
used.
mechanical fasteners…Choosing
Attention to various aspects of the fastener
must be considered. Some of these are listed
below:
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Function of the fastener
Operating environment of the fastener
Type of loading on the fastener in service
Thickness of materials to be joined
Type of materials to be joined
Configuration of the joint to be fastened
mechanical fasteners…Choosing
The choice of the correct fastener may simply
entail fulfilling a requirement for strength (static or
fatigue) or for corrosion resistance.
Conversely, the choice may be constrained by a
complex set of requirements.
The scope and complexity of the fastener system
required is frequently determined by the
consequences of fastener failure.
mechanical fasteners…Choosing
One method of guarding against failure of a new
fastener in a critical application is to sufficiently test
the fastener system prior to use.
A designer must be careful when extrapolate existing
data to an increased size of the same fastener,
– because larger-diameter fasteners can have
considerably lower fatigue endurance limits than
smaller-diameter fasteners.
mechanical fasteners
Is the Zipper a fastener? ….hmm
– What two simple tools make up the zipper?
• Wedge
– door stop and a plow
» Simple machine - incline
• Hook
– The zipper was patented on August 29, 1893
• by Whitcomb Judson, a Chicago mechanical engineer.
– The paper clip is considered a fastener.
• 1867
mechanical fasteners… Functions
To hold parts together.
To hold a completed product to a
– wall, floor or other parts of a building or object.
mechanical fasteners… Types
Non-threaded
Threaded
mechanical fasteners… Non-threaded
Four Major Types
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Nails
Rivets
Staples
Special fasteners
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Cotter pin
Corrugated fasteners
Glazing pins
Skotch fasteners
Four Major Types
mechanical fasteners… Non-threaded
Nails
Hand made nail
– 18th century
Cut nail
– 1790 to 1900
Wire nail
Nails provide one of the best clues to the age of historic buildings,
especially those constructed during the nineteenth century, when
nail-making technology advanced rapidly.
Four Major Types
mechanical fasteners… Non-threaded
Nails
– What simple machine is associated to the nail?
• Wedge
– Other examples: knives, axes and forks
• How many incline planes does a nail have?
– Two
• When a hammer pulls a nail out of the object…
– What are the two simple machines at work?
» Wedge and lever
Four Major Types
mechanical fasteners… Non-threaded
Nails
Nails go back at least to the Roman period.
Nails are usually sold by weight (either in bulk or in
boxes).
– In the US, the length of a nail is designated by its
penny size (d) from the head to the point.
– It is commonly believed that the origin of the term "penny" in
relation to nail size is based on the old custom in England of
selling nails by the hundred.
– A hundred nails that sold for six pence were "six penny"
nails.
Four Major Types
mechanical fasteners… Non-threaded
Nails
Nails go back at least to the Roman period.
Nails are usually sold by weight (either in bulk or in boxes).
–
In the US, the length of a nail is designated by its
penny size (d) from the head to the point.
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Ranges from 2d to 60d.
Anything larger than 10d is referred to as a spike.
It is commonly believed that the origin of the term "penny" in
relation to nail size is based on the old custom in England of
selling nails by the hundred.
A hundred nails that sold for six pence were "six penny" nails.
Four Major Types
mechanical fasteners… special
Nails
HurriQuake Nail (2005-2006)
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The features of the nail are
designed primarily to provide more
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structural integrity,
especially against the forces of
hurricanes and earthquakes.
– Special high-carbon alloy
Four Major Types
mechanical fasteners…special
Nails
HurriQuake Nail (2006)
Tests at the Clemson Wind Load Test Facility confirmed what had
already been stated.
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With equipment to simulate the force of winds, roofs attached with
traditional nails were pulled apart at around 13,500 pounds of force.
At forces up to 16,000 pounds, walls built with the HurriQuake
environment nail showed minimal wall movement.
As the test rig pushed 20,000 pounds, the maximum it was capable of
testing, showing that the HurriQuake environment nail sustained 20,000
pounds of force and still was not sheared or completely pulled out.
Four Major Types
mechanical fasteners… special
Nails
HurriQuake Nail (2006)
…..sustained 20,000 pounds of force
and still was not sheared
or completely pulled out.
Four Major Types
mechanical fasteners… Non-threaded
Common Nails
Common nails have
– larger nail shank diameters than other nails.
Common nails are
– thicker than box, cooler or sinker nails and are
therefore strongest and stiffest.
Common nails are
– always specified for shear wall panels.
Four Major Types
mechanical fasteners… Non-threaded
Common Nails
Used for most medium to
heavy construction work, this
type of nail has a thick head
and can be driven into tough
materials.
Common nails are made from
wire and cut to the proper
length and are available in
sizes 2d through 60d.
Four Major Types
mechanical fasteners… Non-threaded
Finish Nails
Finishing nails have rounded heads that can be driven flush
with the surface of the wood (3d to 10d).
Although they are often countersunk like casing nails, they can
be used without countersinking.
Brads are recommended for light assembly work where the
head should be concealed (.5” to1.5”). Brads look like miniature
finishing nails.
– They are thinner, shorter, and smaller than finish nails.
Escutcheon pins - 3/16” to 2.0”- Round smooth shank, a
diamond point and an oval head. Made in both brass and steel.
Four Major Types
mechanical fasteners… Non-threaded
Casing Nails
These nails are used where the nailhead must be hidden.
– They have small heads and smaller diameters than common
nails.
Casing nails have a conical head, sometimes cupped,
and are somewhat thicker than a finishing nail. A body of a
common nail and head like a finish nail.
– They are sometimes sold already painted and are used to
attach trim.
Four Major Types
mechanical fasteners… Non-threaded
Box Nails
…a nail having a long shank, smooth or barbed, with a
sharp point and a flat head.
Box nails are designed for light construction and
household use.
Sometimes coated with cement, rosin or galvanize to hold
better.
Four Major Types
mechanical fasteners… Non-threaded
Rivets
To secure two or more pieces of material together, a rivet is placed
into a hole cut just a bit larger in diameter than the rivet itself.
Materials - steel, plastic, aluminum, nickel-copper, copper and
stainless.
Steel - Use steel rivets for very heavy duty jobs and when
riveting steel to steel.
Tinners - are solid steel rivets with either a tin or zinc finish.
They are typically used in sheet metal fabrication.
Pop Rivet - A type of rivet that is installed with a tool that pulls a
mandrel through the rivet body performing the riveting function
and then snaps off giving a "popping sound". Sometimes
referred as a “blind” rivet
Four Major Types
mechanical fasteners… Non-threaded
Staples
Staples are U-shaped metal fasteners that are driven into
a surface to hold or secure an object in place.
Staples include flat crown and rounded crown styles.
– Flat crown staples have flat top or crown and are used for
general fastening.
– Rounded crown staples have a curved top and are used to
secure wire, tubing, and other rounded items to flat surfaces.
Staples are available in different sizes, lengths, styles, and
materials.
Fastest growing non-threaded fastener.
Four Major Types
mechanical fasteners… Non-threaded
Special
Cotter pin (cotter key) - Typically made
of wire with a half-circular cross section.
– Once inserted, the two ends of the pin are
bent apart, locking it in place.
– In order to facilitate the initial separation
of the tines, one tine of the cotter pin is
often noticeably longer than the other.
Four Major Types
mechanical fasteners… Non-threaded
Special
Corrugated fasteners - a small strip of corrugated steel with
sharp points on one side; hammered across wood joints in
rough carpentry.
Four Major Types
mechanical fasteners… Non-threaded
Special
Glazing pins - an old method of holding glass in a sash prior to
glazing the window.
Skotch fastener - wood fastener
Four Major Types
mechanical fasteners… Non-threaded
Three ways to install a Nail
Pound with a hammer
Powder actuated tools - means a device for making instantaneous forced entry into
materials by use of a tool, a fastener and an explosive load.
– .22 caliber shot
– .27 caliber shot
– .38 caliber shot
Power
– Electric
– Gas
– Pneumatic Air
Different types of power nailers
– roof, framing, finish, brad, stapler
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