Like FX, I think that this is a bracket that is used to fasten a spiral wave slide to a play structure. How bracket would be translated depends on the type of bracket that is being used. You have many choices for bracket: équerre, fourchette, étrier ou ferrure de fixation, apui, support (as previously given by FX), etc. The open glossary has many choices available. As for the spiral wave slide, my suggestion is "ondulée" for the wavy form of the slide and then a choice of "spirale," "courbe" or "colimaçon" for the curve in the slide.

Plum Cedar Clubhouse Wooden Climbing Frame and Playcenter comprises of two belt swings, acrobatic swing, monkey bar, rock climbing wall, cargo rope ladder with fort access, end ladder, two sets of handgrips, play telescope, clubhouse, double picnic table, enclosed sandpit below the deck, large **spiral wave** slide.
http://www.rawgarden.co.uk/RawGardenSite/pages/product/produ...

Windermere Play Center Wooden Swing Set
Super clubhouse/swingset with the new **spiral wave slide**! Includes high rail spiral wave slide large chalkwall for drawing 2 belt swings 1 glider swing 2x6 overhead monkey ladder cedar rock wall lower sandbox lower cafe table and a sturdy wooden stake anchoring system for safety.
http://www.epinions.com/specs/Windermere_Play_Center_Wooden_...

Playground slides are found in parks, schools, playgrounds and backyards around the world. Slides are constructed of either plastic or metal and they have a smooth surface that is either straight or **wavy/rippled.**
http://en.wikipedia.org/wiki/Playground_slide

Toboggan en colimaçon.
http://fr.wikipedia.org/wiki/Toboggan_(glissoire)

Grâce à un toboggan géant en forme de spirale
http://www.bonnesnouvelles.net/itineraire.htm

de forme ondulée
Balançoire pour enfants Kai Kit à assembler en bois ronds de 10 cm de
section, y compris **toboggan de forme ondulée** et deux planches de balançoire avec
crochets, échelle de corde et matériel de montage, bois traité autoclave, vert.
http://www.holzwelt-helmke.de/pdf/le_jardin_2007_fr.pdf

Tobbogan courbe
http://www.piscinella.com/toboggans-piscine/tobbogan-courbe-...

http://www.wordreference.com/enfr/bracket