Abstract: A right-angle scaffold coupler comprises two jaw assemblies (10A, 10B) each with jaws formed by a closure-plate (12) hinged to a common chassis (11), and having a hand lever (14) hinged (at 21) to the plate (12) with a spirally-coiled spring (25 FIG. 4) as hinge-pin within interleaved finger-lugs (26, 27). A hook-member (15) hinged to the lever (14) engages a lip (19) of the chassis (11) so that depression of the lever (14) pulls the plate (12) towards the chassis (11) in closing the jaws onto a scaffolding tube (13) and clamping to it by over-center action. The spring (25) coils up more tightly during the over-center action allowing resilient displacement between the lugs (26, 27) of hinge (21) to accommodate variations in tube circumference. The jaw surface (17) of the chassis (11) subtends more than 180 degrees to snap fit with the tube (13).

Abstract: A scaffold coupler is actuated by an over-center lever mechanism. The scaffold coupler, which is of resilient plastics, includes a hand lever 13 which is hinged to a jaw 12 that closes upon a base member 11 to clamp tight a scaffolding tube 15. A hook member 14 hinged to the lever 13 engages with a lip 19 of the member 11 so that depression of the lever 13 urges the jaw 12 hard onto the tube 15 and actuates the clamping mechanism by pulling the hook-hinge 22 through `over-center` alignment with the lever-jaw hinge 21 and the hook-lip engagement `hinge` 23. The base-jaw surface 17 subtends more than 180 degrees to snap fit with the tube 15, and opening of the closure jaw 12 is limited by a projection 20 (or otherwise, FIG. 7 ) for support of the tube 15 (FIG. 2). Closing of the jaw 12 may be tripped by entry of the tube 15 (FIG. 6 ), and the jaws may be abrasive-surfaced (FIG. 5 ) to improve grip. The lever 13 may be selectively locked in the actuated condition (FIGS.