Abstract: The collar has a roughly cylindrical metal band and a pair of ears projecting from this band and defining a tightening space between themselves. It also has a tightening device for pulling these ears towards each other. The ears have an extension which is bent around behind each ear away from the other ear and which has a hole for the tightening rod and the tightening device, this hole being lined up with a hole in the forward part of the same area ear. A bracing space is provided between the bent extension and this forward part. The holes of the extension and of the forward part each have an edge portion with a guard which extends into the bracing space and an edge portion without a guard which is aligned with the guard of the other hole.

Abstract: The collar has a substantially cylindrical metal belt (16) and at least one pair of lugs (18, 20) that project relative to said belt and that define a tightening space (22) between them. It also has tightening equipment for bringing the lugs together. Each of the lugs (18, 20) has an extension (19, 21) that is folded back towards the back of said lug, away from the other lug, and that is provided with a hole (22B, 23B) for receiving the tightening rod (24) and the tightening equipment, which hole is situated facing a hole (22A, 23A) in the front portion of the same lug. A bracing space (26, 27) is provided between the folded-back extension and said front portion. Each of the holes (22B, 22A) in the extension (19) and in the front portion (18A) has an edge portion provided with a visor (26B, 26A, 27A) that extends into the bracing space (26, 27), and an edge portion that is not provided with a visor and that extends facing the visor of the other hole.