Spring pin

Last updated
Slotted spring pin (1) and washer (2) used to secure a shaft (3). Spring-type slottet straigt pin labeled num.jpg
Slotted spring pin (1) and washer (2) used to secure a shaft (3).

A spring pin (also called tension pin or roll pin) is a mechanical fastener that secures the position of two or more parts of a machine relative to each other. Spring pins have a body diameter which is larger than the diameter of the hole they are intended for, and a chamfer on either one or both ends to facilitate starting the pin into the hole. The spring action of the pin allows it to compress as it assumes the diameter of the hole. The force exerted by the pin against the hole wall retains it in the hole, therefore a spring pin is considered a self retaining fastener.

Contents

Spring pins may be used to retain a shaft as a journal in a plain bearing, as a type of key to fasten one shaft to another, or to precisely fasten flat faces of mating parts together through symmetric hole locations.

Types

There are two types of spring pins: slotted spring pins and coiled spring pins. [1]

Coiled spring pins

Coiled spring pin. Coiled spring pin.JPG
Coiled spring pin.

A coiled spring pin, also known as a spiral pin, is a self retaining engineered fastener manufactured by roll forming metal strip into a spiral cross section of 2+14 coils. Coiled spring pins have a body diameter larger than the recommended hole diameter and chamfers on both ends to facilitate starting the pin into the hole. The spring action of the pin allows it to compress as it assumes the diameter of the hole.

When coiled spring pins are installed, the compression starts at the outer edge and moves through the coils toward the center. Coiled pins continue to flex after insertion when a load is applied to the pin thus providing excellent performance to counter fatigue in dynamic applications. [2] Coiled spring pins were invented by Herman Koehl circa 1948. [3]

Coiled pins are commercially available in three different duties, standard (ISO 8750), heavy (ISO 8748) and light duty (ISO 8751), which provide for a variety of combinations of strength, flexibility and diameter to suit different mating host materials and performance requirements. Typical materials for coiled spring pins include high carbon steel, stainless steel and alloy 6150.

Coiled pins are used extensively in cosmetic cases, automotive door handles and locks, and latches as hinge pins. They are also used as pivots and axles, for alignment and stopping, to fasten multiple components together—such as a gear and shaft—and even as ejector pins to remove motherboards from PCs. The automotive and electrical industries use coiled pins in such products as steering boxes and columns, pumps, electric motors and circuit breakers.

International Standards

Slotted spring pins

Slotted spring pin. Spring pin heavy duty.svg
Slotted spring pin.

Slotted spring pins are cylindrical pins rolled from a strip of material with a slot to allow the pin to have some flexibility during insertion. Slotted spring pins are also known as roll pins, sellock pins or "C" pins. These are also often referred to as spirol pins - pronounced ‘spiril’ in the Birmingham area.

See also

Related Research Articles

<span class="mw-page-title-main">Zipper</span> Device for binding the edges of an opening of fabric or other flexible material

A zipper, zip, fly, or zip fastener, formerly known as a clasp locker, is a commonly used device for binding together two edges of fabric or other flexible material. Used in clothing, luggage and other bags, camping gear, and many other items, zippers come in a wide range of sizes, shapes, and colors. In 1892, Whitcomb L. Judson, an American inventor from Chicago, patented the original design from which the modern device evolved.

<span class="mw-page-title-main">Rivet</span> Permanent mechanical fastener

A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the tail. On installation, the rivet is placed in a punched or drilled hole, and the tail is upset or bucked, so that it expands to about 1.5 times the original shaft diameter, holding the rivet in place. In other words, the pounding or pulling creates a new "head" on the tail end by smashing the "tail" material flatter, resulting in a rivet that is roughly a dumbbell shape. To distinguish between the two ends of the rivet, the original head is called the factory head and the deformed end is called the shop head or buck-tail.

<span class="mw-page-title-main">Fastener</span> Hardware device that mechanically joins or affixes two or more objects together

A fastener or fastening is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or dismantled without damaging the joining components. Steel fasteners are usually made of stainless steel, carbon steel, or alloy steel.

<span class="mw-page-title-main">Washer (hardware)</span> Thin plate with a hole, normally used to distribute the load of a threaded fastener

A washer is a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a bolt or nut. Other uses are as a spacer, spring, wear pad, preload indicating device, locking device, and to reduce vibration.

<span class="mw-page-title-main">Screw thread</span> Helical structure used to convert between rotational and linear movement or force

A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. A screw thread is the essential feature of the screw as a simple machine and also as a threaded fastener.

<span class="mw-page-title-main">Pin</span> Fastening device

A pin is a device, typically pointed, used for fastening objects or fabrics together. Pins can have the following sorts of body:

An interference fit, also known as a pressed fit or friction fit, is a form of fastening between two tightfitting mating parts that produces a joint which is held together by friction after the parts are pushed together.

<span class="mw-page-title-main">Nail gun</span> Type of power tool

A nail gun, nailgun or nailer is a form of hammer used to drive nails into wood or other materials. It is usually driven by compressed air (pneumatic), electromagnetism, highly flammable gases such as butane or propane, or, for powder-actuated tools, a small explosive charge. Nail guns have in many ways replaced hammers as tools of choice among builders.

<span class="mw-page-title-main">Set screw</span> Type of screw

In American English, a set screw is a screw that is used to secure an object, by pressure and/or friction, within or against another object, such as fixing a pulley or gear to a shaft. A set screw is normally used without a nut, being screwed instead in a threaded hole drilled in only one of the two objects to be secured. A set screw is often headless and threaded along its entire length, so that it will sit entirely inside that hole; in which case it may be called a grub screw or blind screw.

<span class="mw-page-title-main">Sex bolt</span> Type of mating fastener

A sex bolt is a type of mating fastener (nut) with a barrel-shaped flange and protruding boss that is internally threaded. The bolts sits within the components being fastened, and the flange provides the bearing surface. The sex bolt and accompanying machine screw sit flush on either side of the surfaces being fastened.

<span class="mw-page-title-main">Dzus fastener</span>

The Dzus fastener, also known as a turnlock fastener or quick-action panel fastener, is a type of proprietary quarter-turn spiral cam lock fastener often used to secure skin panels on aircraft and other high-performance vehicles. It is named after its inventor William Dzus.

A retaining ring is a fastener that holds components or assemblies onto a shaft or in a housing/bore when installed - typically in a groove - for one time use only. Once installed, the exposed portion acts as a shoulder which retains the specific component or assembly. Circlips are a type of retaining ring.

<span class="mw-page-title-main">Flange nut</span>

A flange nut is a nut that has a wide flange at one end that acts as an integrated washer. This serves to distribute the pressure of the nut over the part being secured, reducing the chance of damage to the part and making it less likely to loosen as a result of an uneven fastening surface. These nuts are mostly hexagonal in shape and are made up of hardened steel and often coated with zinc.

In mechanical engineering, a key is a machine element used to connect a rotating machine element to a shaft. The key prevents relative rotation between the two parts and may enable torque transmission. For a key to function, the shaft and rotating machine element must have a keyway and a keyseat, which is a slot and pocket in which the key fits. The whole system is called a keyed joint. A keyed joint may allow relative axial movement between the parts.

<span class="mw-page-title-main">Screw</span> Type of fastener characterized by a thread wrapped around a cylinder core

A screw and a bolt are similar types of fastener typically made of metal and characterized by a helical ridge, called a male thread.

<span class="mw-page-title-main">R-clip</span> Type of fastener made of a springy material

An R-clip, also known as an R-pin, R-key, hairpin cotter pin, hairpin cotter, bridge pin, hitch pin clip or spring cotter pin, is a fastener made of a durable but flexible material, commonly hardened metal wire, resembling the shape of the letter "R".

ASTM F568M is an ASTM International standard for metric bolts, screws and studs that are used in general engineering applications. It is titled: Standard Specification for Carbon and Alloy Steel Externally Threaded Metric Fasteners. It defines mechanical properties for fasteners that range from M1.6 to 100 in diameter. The standard was withdrawn in 2012. and has been replaced by ISO 898-1

<span class="mw-page-title-main">Hex key</span> Driver for hexagonal socketed bolts or screws

A hex key is a simple driver for bolts or screws that have heads with internal hexagonal recesses (sockets).

<span class="mw-page-title-main">Wrench size</span>

Width across flats is the distance between two parallel surfaces on the head of a screw or bolt, or a nut, mostly for torque transmission by positive locking.

References

  1. Korane, Kenneth, Fasteners that maximize assembly life. Machine Design, October 19, 2009
  2. Schilhansl, M.J, The Pin. Featured presentation at The American Society of Mechanical Engineers semiannual meeting. Detroit, Michigan. June 15–19, 1958
  3. Camillo, Jim, Fastening: Coiled Pins for Assembly. Assembly Magazine, September 27, 2010

Further reading