A brief history and human factors of Zippers

1. ‐submitted by Praveen Uchil
A brief
history of
Zippers
A zipper i a slide f t
i is lid fastener with ith
two edges of teeth attached
to a fabric tape. The teeth lock
into a snug fit when they arc
drawn together by a slide.
When the slide is pulled back,
the teeth separate.
The zipper was invented by
Whitcomb L. Judson. a
Chicago.
Illinois. mechanical engineer. to
relieve the tedium of fastening
by hand the fashionable high‐
buttoned boots of the time .
Judson' fastener called th
J d ' s f t ll d the
Clasp Locker and patented in
1893. consisted of a movable
guide that meshed together
two sets of hooks and eyes.
Judson also invented a machine
to mass produce his fasteners
cheaply. However: these
machines broke down Slider engagement mechanism involves
frequently and the Judson’s interlocking of clasps along vertical to
f t
fasteners had a way of
h d f axis of motion vertical motion unlike
spontaneously unfastening. modern day zippers

2. Sundback ‘ s
invention (1913)
( ) Sunback’s patent on separable
fastener
f t
It was Gideon Sundback( 1880‐ 1956),
a Swedish engineer who developed the
first really practical and successful slide
fastener.
Sundback ' s 1913 invention used
small interlocking teeth that were
flexible and remained locked together.
Sundback also invented efficient
machinery to produce improved
fastener cheaply.
fastener cheaply
Although the slide fastener was now
ready to be mass produced for wide
spread usage clothing manufacturers
continued to ignore it except for one
which contracted in 1918 to supply the Detailed view showing manner of locking and
g g
United States Navy with flying suits unlocking
equipped wih the device. Judson' s
company suddenly had an order for
thousands of the fasteners. .
Manufacturers began to realize how
useful the fastener could be. Soon it
useful the fastener could be Soon it
appeared in gloves and tobac.co
pouches.
In 1923 the B.F. Goodrich Company
added the slide fasteners to their
rubber galoshes calling this new
footwear design Zipper which from
f d i Zi hi h f
then on became the popular name for
the fastener itself .
Zippers finally appeared on clothing,
first in men's pants. and. in the late
1920s. In women’s garments.
g
Today' s design is little changed from
Sundback’s original

3. Human Factors
in Zipper Design
Typical Usage Scenario:
When the user want to fasten or unfasten the zipper,
When the user want to fasten or unfasten the zipper
he drags the pull tab along the chain. He may use his
other arm for making a convenient and swift
movement.
Product dimensions concerned to human factors:
Dimensions of puller tab:
Length, width, thickness of the puller tab should be
selected as such to accommodate proper gripping using
thumb and fore fingers. On the other hand the design
requires that in order to hide the zipper identity, its
dimensions should be as small as possible.
di i h ld b ll ibl
Length of tape (Chain):
Length of the tape should be as minimum as possible to
reduce the pulling effort required to zip.
Force required to zip and unzip:
Components of a zipper
Force required to zip and unzip should be minimum as
possible to reduce the effort required to move and local
straining of thumb and forefingers.
Force required to hold and pull:
Maximum Locking Force that can be provided
between the teeth of the zippers depends on quality of
fit between the teeth and t yield strength of the
material. Application like zippers used in a canvas sling
pp pp g
to help lift dolphins out of municipal aquariums require
very strong interlocking between the teeth.

4. Human Factors
in Zipper Design
Probelms with existing zippers:
Current Zippers that found in everyday
Current Zippers that found in everyday
products, many of the times needs both of
the hand to fasten or unfasten. This is because
when angle between left and right side of the
zipper becomes obtuse, they interfere with
side walls of the slider blocking the zipping
action. During this the user further tries to zip
by applying more force which results in
movement of zipper and the surrounding
cloth as a whole, making the scenario verser.
Accidents:
Another serious problem which could lead to
p
adverse consequences is penis skin getting
caught in zipper. There are lot of instances of
such accident which often are not revealed.
Small children are more prone to such
accidents when they do not wear underwear.
Scope for improvement:
Presently available zippers needs
both of our hands to be used. If the zippers Remedies for
can be used effectively and smoothly in one Penile zipper entrapment:
hand it would be a remarkable innovation and a simple and less threatening
will have large market potential. approach using mineral oil is
pp g
Any modification in teeth Configu shown in above fig.
‐ration to prevent the penile entrapment
could be a very significant development in
zipper design.