A cam and groove coupling, also called a camlock fitting, is a form of

hose coupling A hose coupling is a connector on the end of a hose to connect (or ''couple'') it with another hose or with a tap or a hose appliance, such as an irrigation sprinkler. It is usually made of steel, brass, stainless steel, aluminium or plastic ...

. This kind of coupling is popular because it is a simple and reliable means of connecting and disconnecting hoses quickly and without tools.

Standards

Traditionally manufactured to US Military Specification MIL-C-27487, this specification covered the dimensions and machining tolerances, materials, closing torque, part numbers, pressure ratings, finish, inspection procedures and packing requirements. Compliance to this specification ensured inter-changeability of parts from different manufacturers. In 1998, the specification A-A-59326 replaced MIL-C-27487. In Europe the standard BS EN 14420-7 applies as well as the German DIN 2828 standard. Products produced to DIN 2828 are interchangeable with those made to the original MIL-C-27487 but have differences in the hose tail design, thread, part number and other details.

Function

The cams at the end of each lever on the female end align with a circumferential groove on the male end. When the levers are rotated to the locked position, they pull the male end into the female socket, creating a tight seal against a

gasket Some seals and gaskets A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. It is a deformable material that is used to c ...

within the female socket. The arms lock into position using over-center geometry, preventing accidental decoupling. Further, lever safety pins are common features for additional security, and female-end "self-locking" levers are also available. Because the groove is cut all the way around the male end, there is no specific rotational alignment necessary to couple, as there would be with threaded connectors, and there is no opportunity for cross-threading. This results in a fast, error-resistant coupling operation. Because the compression between the two fittings is limited by the size of the cams on the end of the levers and the rotation of the levers themselves, there is also no possibility of over- or under-tightening the fitting; the pressure against the sealing gasket is effectively constant from one coupling operation to the next, reducing possibility of leaks.

Materials and uses

Cam and groove fittings are commonly available in several materials, including stainless steel,

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...

brass Brass is an alloy of copper (Cu) and zinc (Zn), in proportions which can be varied to achieve different mechanical, electrical, and chemical properties. It is a substitutional alloy: atoms of the two constituents may replace each other wit ...

, and

polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins a ...

. Because there are no threads to become fouled, cam and groove couplings are popular in moderately dirty environments, such as septic tank pump trucks and chemical or fuel tanker trucks. The system is especially well suited to a situation where frequent changes of hoses are required, such as for petroleum trucks, etc. As examples of industrial application, cam and groove fittings can be used in a system where rapid filling of chemical drums takes place, or by factories that have needs of dye, paint, and ink medium transfers. Note: Cam and Groove couplings are not recommended for any type of

compressed gas A compressed fluid (also called a compressed or unsaturated liquid, subcooled fluid or liquid) is a fluid under mechanical or thermodynamic conditions that force it to be a liquid. At a given pressure, a fluid is a compressed fluid if it is at ...

service, including steam or air.

Types and sizes

Generally speaking, the most common types of cam and groove coupling are the following types. The letter codes are the common designations, while the roman numeral codes come from the GSA

CID CID may refer to: Film * ''C.I.D.'' (1955 film), an Indian Malayalam film * ''C.I.D.'' (1956 film), an Indian Hindi film * ''C. I. D.'' (1965 film), an Indian Telugu film * ''C.I.D.'' (1990 film), an Indian Hindi film Television * ''CID'' ( ...

A-A-59326 standard: *Type A or Type I: adapter (male end) with female thread, e.g. BSP or NPT *Type B or Type VII: coupler (female end) with male thread, e.g. BSP or NPT *Type C or Type VI: coupler with shank (hose barb) *Type D or Type V: coupler with female thread *Type E or Type II: adapter with shank *Type F or Type III: adapter with male thread *Type IV: adapter with flange, TTMA (Truck Trailer Manufacturer's Association) *Type VIII: coupler with flange, TTMA *Type DC or Type IX: dust caps (female) *Type DP or Type X: dust plugs (male) Apart from these basic types, the hose/pipe connection side of a cam and groove coupler can be of various other types such as with a

flange A flange is a protruded ridge, lip or rim, either external or internal, that serves to increase strength (as the flange of an iron beam such as an I-beam or a T-beam); for easy attachment/transfer of contact force with another object (as the f ...

, for

butt welding Butt welding is when two pieces of metal are placed end-to-end without overlap and then welded along the joint (as opposed to lap joint weld, where one piece of metal is laid on top of the other, or plug welding, where one piece of metal is ins ...

to a container, for truck use with a

sight glass Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflec ...

, etc. These couplings are available in the following diameters:

Gallery

Image:Camlock type B.JPG Image:Camlock type C.JPG Image:Camlock type D.JPG

References