Pipe couplings RK22 black

The idea behind the tube connector system is simple. Every joint in a frame, a workbench, a cart or a machine guard gets a connector with the right number of connections, and the whole structure is assembled as a kit from cut standard tube. It calls for neither a welding certificate nor surface finishing, and the build can be changed when the needs change: a leg is moved, a section is replaced, a shelf is added without taking the rest apart.

Work through the build before you order. Every joint adds a few millimeters per connection, so the cut lengths are set after the connector types are chosen, not before. Dry assemble the frame loosely before the parts are tapped together; that gives you time to adjust a cut length or change a connector type while the structure can still be pulled apart without tools. Write a simple pick list per joint while you are at it, that makes both ordering and assembly faster.

PA6 is a tough engineering plastic that damps knocks and vibration better than all metal joints. The surface is matte black and colored all the way through; scratches from assembly and moving are barely visible. The material handles oils, greases and normal cleaning agents and never rusts, which makes the connectors useful even in wash bays, commercial kitchens and other damp environments where painted or welded joints quickly look worn. The plastic also insulates both electrically and thermally, so the joints are neither cold to touch nor conductive, a detail that is appreciated in handles and railings.

Choose the version by the outside dimension and wall thickness of the tube. The press fit relies on the inside dimension of the tube, so two tubes with the same outside dimension but different wall thickness call for different versions; measure with a caliper if you are unsure and check against the dimensions in the manufacturer's data sheet. The variant list here on the page shows exactly which combinations the series covers, so you never have to guess. Tube in ordinary structural steel, stainless or aluminum works just as well; it is the dimensions that govern, not the tube material.

We see the connectors in workshops that build fixtures and material racks, at store fitters who assemble display stands and in maintenance departments that repair or rebuild existing tube structures. Feel free to combine several connector types from the same program; the whole range of tube connectors, from straight joints to six way joints, is in the Fasteners category here in the web shop. Many builds mix all plastic connectors in lightly loaded points with steel core reinforced ones in the load carrying points, so that cost and stiffness end up where they do good.

The connector is molded in one piece in PA6 without metal reinforcement. That keeps the weight down and is plenty for shelves, racks and fittings where the joint is mainly held together by the stiffness of the tubes themselves. If you need to bolt the structure down or hang a load directly in the joint, there are sister versions with a molded in steel core and an internal thread in the same range.

RK22 is a hinged two way connector for square tubes in nylon PA6. The series covers square tube 20x20, 25x25 and 40x40 mm with a wall thickness of 2.0 mm, and you pick the dimension as a variant here on the product page. The connector is pressed into the tube ends and builds the structure together without welding; cut the tubes, put the connector in and tap the parts together with a rubber mallet.

The hinge lets the angle between the tubes be set steplessly, which opens up angled braces, sloping surfaces and structures that are not square. A diagonal brace that stiffens a tall rack is the typical example; cut the brace, angle the connector and tap it home.

Do you need the data sheet or a complete pick list for the build? Contact us.