g the embodiments in which the coil shape is closer to a semicircle than it is to a ???U??????see, for example, FIG. 22.)The shape of the inner wall 24 is designed to be placed partially around a cylindrical object, such as a pipe, and as such it can be easily inserted about, and later removed from, a long length of two pipe sections at a location where a joint is to be formed with the two pipe se