Curtain grommets, used among others in .">shower curtains.
A grommet is a ring or edge strip inserted into a hole through thin material, typically a sheet of
textile
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the ...
fabric,
sheet metal
Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Sheet metal is one of the fundamental forms used in metalworking, and it can be cut and bent into a variety of shapes.
Thicknesses can vary significantly; ex ...
or composite of carbon fiber, wood or honeycomb. Grommets are generally flared or collared on each side to keep them in place, and are often made of
metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
,
plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
, or
rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, an ...
. They may be used to prevent tearing or abrasion of the pierced material or protection from abrasion of the insulation on the wire, cable, line being routed through the penetration, and to cover sharp edges of the piercing, or all of the above.
A small grommet may also be called an eyelet, used for example on shoes, tarps and sails for lacing purposes.
Grommets in electrical applications are referred to as "insulating bushings". Most common are molded rubber bushings that are inserted into hole diameters up to 2″ (51 mm). There are many hole configurations from standard round to assorted U-shapes. Larger penetrations that are irregular in shape as well as long straight edges are often fitted with extruded or stamped strips of continuous length, referred to as "grommet edging". This type of protective bushings is quite common in applications that range from telecom switches and data center cabinets to complex and dense wire/cable and even hydraulic tubing in aircraft, transportation vehicles and medical equipment.
As reinforcement or crafting
Metal eyelets and an eyelet setting tool.![Seaman's chest](https://upload.wikimedia.org/wikipedia/commons/a/a3/Seaman%27s_chest.jpg)
Grommets are typically used to reinforce holes in
leather
Leather is a strong, flexible and durable material obtained from the tanning, or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle, sheep, goats, equine animals, buffalo, pigs and hog ...
,
cloth
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the ...
,
shoes
A shoe is an item of footwear intended to protect and comfort the human foot. They are often worn with a sock. Shoes are also used as an item of decoration and fashion. The design of shoes has varied enormously through time and from culture t ...
,
canvas and other
fabric
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not th ...
s.
They can be made of
metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
,
rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, an ...
, or
plastic
Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...
, and are easily used in common projects, requiring only the grommet itself and a means of setting it. A simple
punch
Punch commonly refers to:
* Punch (combat), a strike made using the hand closed into a fist
* Punch (drink), a wide assortment of drinks, non-alcoholic or alcoholic, generally containing fruit or fruit juice
Punch may also refer to:
Places
* Pun ...
, a metal rod with a
convex
Convex or convexity may refer to:
Science and technology
* Convex lens, in optics
Mathematics
* Convex set, containing the whole line segment that joins points
** Convex polygon, a polygon which encloses a convex set of points
** Convex polytop ...
tip, is often sold with the grommets. It can be struck with a
hammer to set the grommet.
It can alternatively be set with an electronic, pneumatic, or gas-powered machine. There are also dedicated grommet presses with punch and
anvil, as shown in the picture, ranging from inexpensive to better-quality tools, which are somewhat faster to use.
Typical applications are footwear for boot and shoe laces, in laced clothing such as
corsets, in
flags for hoisting, and in curtains and other household items that require hanging from hooks, as when they are used in conjunction with tensioner rods for shower curtains. The grommet prevents the cord from tearing through the hole, thereby providing structural integrity. Small grommets are also called eyelets, especially when used in clothing or crafting. Eyelets may be used purely decoratively for crafting. When used in sailing and various other applications, they are called
cringle
A cringle is an eye through which to pass a rope. In nautical settings, the word refers to a small hole anywhere along the edge or in the corner of a sail, rimmed with stranded cordage and worked into the boltrope. Typically it encloses a meta ...
s. Sometimes field workers refer to them as grunyons.
Maritime use
Traditionally, rope grommets have been widely used on
sailing ships
A sailing ship is a sea-going vessel that uses sails mounted on masts to harness the power of wind and propel the vessel. There is a variety of sail plans that propel sailing ships, employing square-rigged or fore-and-aft sails. Some ships ca ...
in a variety of ways. They have been utilized as chest handles or on row boats as a soft oar lock. They are a rope ring that is made by first disassembling the rope then re-weaving the strands to the desired size.
Use in electrical equipment
For cable protection
Holes in metal or another hard material will often have sharp edges.
Electrical
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
wire
Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm
A wire is a flexible strand of metal.
Wire is c ...
s,
cord
Cord or CORD may refer to:
People
* Alex Cord (1933–2021), American actor and writer
* Chris Cord (born 1940), American racing driver
* Errett Lobban Cord (1894–1974) American industrialist
* Ronnie Cord (1943–1986), Brazilian singer
* Co ...
,
rope
A rope is a group of yarns, plies, fibres, or strands that are twisted or braided together into a larger and stronger form. Ropes have tensile strength and so can be used for dragging and lifting. Rope is thicker and stronger than similar ...
, lacings, or other soft vulnerable material passing through the hole can become
abraded or cut, or electrical insulation may break due to repeated flexing at the exit point of the casing of a junction box for example.
Rubber, plastic or plastic coated metal grommets are used to avoid this. Tight fitting rubber grommets can also prevent the entry of dirt, air, water, etc.
The smooth and sometimes soft inner surface of the grommet shields the wire from damage.
Grommets are generally used whenever wires pass through punched or drilled
sheet metal
Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Sheet metal is one of the fundamental forms used in metalworking, and it can be cut and bent into a variety of shapes.
Thicknesses can vary significantly; ex ...
or plastic casings for this reason.
Molded and continuous strip grommets, also known as edge grommets, are manufactured in a wide variety of sizes and lengths expressly for this purpose; they are usually a single piece which can be inserted by hand. Two-piece hard plastic devices are available which also grip the wire that passes through. These are called
strain relief bushings and are often used to insulate, anchor, and protect power cords where they enter panels. Preventing a tug or twist on the wire from stressing the electrical connections inside the connected equipment. Sleeved grommets have a flexible extension (sleeve), usually tapered or moulded to flex increasingly towards the free end in order to reduce fracturing of electrical insulation.
To minimize vibration
Grommets made of rubber or other elastic material are also used to minimize the transmission of vibration. They were widely used for mounting shock-sensitive
computer disk drive
Disk storage (also sometimes called drive storage) is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is ...
s, particularly in equipment subject to vibration or jarring, but are not usually used with more robust modern drives. The screws that hold the drive in place pass through grommets that decouple it acoustically from the chassis. Grommets are used in a similar way to acoustically isolate
electronic circuit components that are susceptible to
microphonism
Microphonics, microphony, or microphonism describes the phenomenon wherein certain components in electronic devices transform mechanical vibrations into an undesired electrical signal (noise). The term comes from analogy with a microphone, which ...
caused by mechanical vibration or jarring.
Surgical grommets
In chronic cases of
otitis media
Otitis media is a group of inflammatory diseases of the middle ear. One of the two main types is acute otitis media (AOM), an infection of rapid onset that usually presents with ear pain. In young children this may result in pulling at the ear, ...
with effusions present for months, surgery is sometimes performed to insert a grommet, called a "
tympanostomy tube
Tympanostomy tube, also known as a grommet or myringotomy tube, is a small tube inserted into the eardrum in order to keep the middle ear aerated for a prolonged period of time, and to prevent the accumulation of fluid in the middle ear. The ope ...
" into the
eardrum to allow air to pass through into the middle ear, and thus release any pressure buildup and help clear excess fluid within.
This is also a correcting measure for a
patulous Eustachian tube
Patulous Eustachian tube (PET) is the name of a physical disorder where the Eustachian tube, which is normally closed, instead stays intermittently open. When this occurs, the person experiences autophony, the hearing of self-generated sounds. ...
(when air moves to and from the middle ear with each breath making the eardrum flap).
Gallery
File:Aman Eyelets.jpg, Brass eyelets.
File:Shoelaces 20050719 002.jpg, Mountain boot with 6 eyelets, 4 hooks, followed by 2 additional eyelets.
File:Alphabet eyelets.jpg, alt=Alphabet eyelets, Alphabet eyelets
See also
*
Blind rivet
*
Cable grommet
A cable grommet is a tube or ring through which an electrical cable passes. They are usually made of rubber or metal.
The grommet is usually inserted in holes in certain materials in order to protect, improve friction or seal cables passing throu ...
*
Cringle
A cringle is an eye through which to pass a rope. In nautical settings, the word refers to a small hole anywhere along the edge or in the corner of a sail, rimmed with stranded cordage and worked into the boltrope. Typically it encloses a meta ...
*
Shoulder washer
References
External links
*
*
{{Sewing
Fasteners
Footwear components
Implants (medicine)
Textile closures