Abstract: An elastomeric disc for use on a pipeline pig of the type having a longitudinal body supported centrally within a pipeline for movement by fluid flow therethrough, the disc being in the form of a unitary elastomeric member having an outer peripheral surface concentric with the pipeline pig body longitudinal axis and having an inner portion of selected thickness with means for attachment to the pipeline pig body whereby the disc is supported in a plane perpendicular the pipeline line axis, the disc member having an integrally formed circumferential outer portion, the outer portion being of increased thickness in relation to the spacing thereof from the disc center, the outer peripheral surface being defined by first and second intersecting frustraconical surfaces, one of the surfaces being parallel to the inner wall of the pipeline through which the disc is moved in a first direction and the other of the surfaces being parallel to the inner wall of the pipeline when the disc is moved in a second direction.

Abstract: A rotary die cutting cover for use on a die cutting cylinder, in which the cylinder has a cylindrical external surface and a recess slot extending the length of the cylindrical surface, the cover being formed of a mat of resilient, flexible material having integral increased thickness end portions which are received in the cylinder recess slot and in which one mat end portion has a bottom surface having a narrow slot therein extending the width of the mat, the narrow slot allowing the mat end portion to compress as it is inserted into the cylinder recess slot.

Abstract: A method of making a foam pig having a highly textured and tough surface for use in cleaning the interior wall of a pipe line, the pig being formed by heating a metallic mold which defines the exterior configuration of the pig, injecting urethane base foam mixture into the heated mold, and curing the injected urethane foam before removing the cured pig from the mold. The mold should be heated to a temperature sufficient to produce a tough surface texture on the completed pig defined by closely spaced indentations of about one-half to three millimeters in depth, the indentations being formed by bubbles in the urethane foam base mixture on the surface of the mold.

Abstract: An improved pig for use in a pipeline is provided in which the basic structure including a body and the cup portions integrally formed of a unitary design, the body being of an elongated cylindrical configuration, including at least a forward and rearward cup extending from the body, the diameter of the cups being at least two and not more than five times the diameter of the body, the normal diameter of the cups in non-used condition being slightly greater than the internal diameter of the pipeline for which the pig is dimensioned and the length of the body being at least 11/2times the normal diameter of the cups. In a preferred arrangement the body is hollow or tubular for a substantial portion of its length and has an insert of a tubular rigid material; the thickness of the cups is less adjacent the body and the increases in thickness towards the peripheral surface; and the rearward cup has pressure equalizing openings.