Snap to it for fast assembly

New snap-in devices for sheet metal enclosures include a quarter turn latch and a handle. The advantages of the Snap-Line series from Dirak, whose development we described in the March 2006 edition of the magazine, are that provided a suitably shaped hole has been stamped out, they only take a moment to insert but are then more securely attached than many products that require the use of self tapping screws. A quarter turn latch for a 32 x 20mm cut out and a new bowed handle will be unveiled by Dirak at this year’s Hanover Fair. According to marketing manager Udo Kemper: “The latch is designed to be flush with the front surface of the door and snaps into a rectangular hole with two side lobes, which ensures that it cannot be turned round.” At the same time, Dirak has brought out a free, pocket sized 82 page guide book, with a chapter at the back about some new application areas for the technology which, it says, are “realistic but not yet finalised”. For example, a handle or other device could be snapped to a tube by using an adaptor that is curved to match the tube on the outside and flat on the reverse side or shaped to match whatever is being snapped into it. The book also suggests snapping devices onto T-channel frames. There are many ways that snap fasteners could be used for the assembly of sheet metal furniture, but the book also offers two approaches for snap joining to softer materials such as wood or plastic. One would be to use an “indirect snap fastener”. In this scheme, an elongated hole is sunk into the carrier material, which receives an insert from the back. This has two offsets into which the wings of the snap fastener can go, and a large base on the back to distribute pressure and tension to prevent its being pulled out. The device to be snapped in is then inserted from the front. The alternative strategy would be to use what is termed a “direct snap fastener”, with a securing screw for the sheet metal or other part to be attached. The snap element would have serrated wings. After insertion into the installation opening in the soft substrate, the securing screw would be tightened so as to push the serrations into the carrier material. These could be used with both open and blind holes. Variations in hole sizes would be accommodated by the use of the securing screw. Dirak believes that its technology could be safely used to join scaffolding poles as a more secure alternative to screws and nuts. It is also possible to connect beams using D-Snap technology, and to connect panels to beams giving a folded edge to a panel to provide a hinge effect and removable snap joiners to secure the free side. Pointers * New Snap-Line products for sheet metal enclosures are constantly being developed * New ideas include ways of snap fastening to softer materials such as wood and plastic * It may even be possible to devise a snap-together technology to fasten scaffolding poles