Abstract: A welding collar contains a collar body of fusible plastic and a heater coil, disposed in its inside surface, which is spaced apart from a free collar end by a front zone. This welding collar is improved in that pipelines with ends which are not precisely cylindrical, and especially pipelines made from material in rolls, can be welded in a problem-free and reliable manner. The sum of the length of the front zone and the axial length of an inner zone adjoining the heater coil, with which the inserted pipe comes in contact, is at least approximately equal to the length of the heater coil. The insertion depth is greater by at least a factor of 1.4 than the inside diameter of the collar body.

Abstract: A push-in coupling for pipes contains a sleeve body (2) and a holding means, especially with a clamping body (6), for connecting a pipe end (3, 4) to the sleeve body (2). This push-in coupling permits proper handling with little effort during assembly, and insofar as possible prevents the danger of faulty assembly. A sliding body (50) is disposed within the sleeve body (2), the sliding body (50) being made independently of the holding means. The sliding body (50) contains a striker (52) which upon insertion of the pipe end (3, 4) is pushed over an edge (60), and upon reaching a given depth of insertion of the pipe end (3, 4) strikes against a surface (62) producing a detectable signal such as an acoustical signal and/or a vibration signal.