Abstract: Apparatus for making plastic screen panels, and especially abrasion-resistant mining screens, includes a large rotary screen drum member on which an extruded, profiled cross-section screen surface-forming wire is helically wound at a pitch which will produce the desired screen slot width. Immediately adjacent the drum member is a rod-positioning mechanism from which a plurality of screen panel support rods are sequentially fed from a stack and welded to the wires on the drum surface in a direction parallel to the drum axis and transverse to the surface wires. The welding is done with a double-edged heater bar which is temporarily placed in contact with the rod and drum before the rod is forced against the drum. The screen drum is indexed after each support rod is attached to it by an angular amount sufficient to provide the desired spacing on the finished panel.

Abstract: A garage door panel apparatus is formed with a metal sheet and having an insulating barrier strip connecting the inner and outer metal sheets of each panel to block conduction of heat between the front and back metal sides. The barrier strip holds front and back sheets together and provides a support for the weatherstrip. The metal sheet is filled with a rigid polymer foam which acts as insulation and support for the metal sheet. The method provides for making of a garage door panel in which the metal sheet of the front and back panels are joined by a barrier strip which holds the sheets together in a spaced relationship to each other. The expansion of the polymer foam within the door panel metal sheet increases the pressure to lock the barrier strips onto the edges of the panel's metal sheet. Thus, the barrier strip locks the front and back metal sheets together while forming an insulator against the conduction of heat through the metal and simultaneously providing a support for weatherstripping.

Abstract: A fiber reinforced plastic well screen including a slotted central section and unslotted end fitting portions is formed by manipulating a single bundle of resin-coated filaments longitudinally and circumferentially relative to a mandrel. The mandrel has a series of helically grooved segments which cooperate with each other to cause the filament bundle to form the slotted central section. Longitudinal wraps, which are looped under tension from one end of the mandrel to the other in the region between each adjacent pair of segments, are intimately bonded to all of the helical circumferential wraps which form the central section as well as those that form the end fitting portions. One removable end cap portion of the mandrel is preferably externally threaded to produce an integral internal thread in the formed well screen. A tubular internal sleeve portion of the mandrel is removable to permit the helically grooved segments to be collapsed inwardly after the well screen is cured.

Abstract: Improved method of joining a rigid thermoplastic fitting to a rigid thermoplastic well screen having longitudinal support rods utilizes pressure and friction generated heat to bond a reduced diameter tubular, rigid thermoplastic sleeve portion of the fitting to the inner surface of the screen. The method permits the joining, without the use of solvents, of screens and fittings of PVC, polypropylene, or ABS, for example, which have the same outer diameters. The sleeve portion of the fitting has an outer diameter which is greater than the inner diameter of the well screen. The assembly method requires that the parts to be mated be rotated rapidly relative to each other as they are forced axially into interfering, telescopic engagement. The overlapping members are fused along a generally conically tapered plane with the material which is melted during rotation being deposited in the circumferential spaces between the screen's support rods.

Abstract: Assembly apparatus for a wear resistant plastic mining screen, preferably one made out of wires formed by extruding urethane around a rigid steel core, includes a feed roll having spaced grooves for receiving elongated profile wires which define the working surface of the screen. A support rod positioning member is mounted at a welding station to frictionally receive a screen support rod on its top side and then be flipped over to position the support rod above the profile wires which pass transversely under it. A welding bar having heated fin portions on its upper and lower sides is then passed between and in contact with the support rod and the profile wires to slightly melt them. The welding bar is then quickly removed and the support rod is quickly moved downwardly against the profile wires and held until the integral joints formed at each intersection are solidified. Additional support rods are welded to the profile wires at spaced intervals until the desired screen length has been reached.