An anchoring device for a pipe coupling including an annular channel of generally U-shaped cross-section. The channel has a web portion with flanges and projecting radially inwardly. A frusto-conical gripping ring is located in the channel with its outer edge inside the web portion adjacent one of the flanges and its inner edge adjacent the other flange and projecting inwardly beyond this latter flange. The annular channel forms an incomplete ring and is compressible circumferentially. The anchoring device is fitted inside a clamping device, which fits around a pipe coupling. The clamping device has a tensioning for tightening the clamping device around the pipe, compressing the annular channel and causing the inner edge of the frusto-conical gripping ring to engage the outer surface of the pipe and thus grip the pipe.