Abstract: A multilayer circuit board consisting of multiple circuit layers supported on sheets of PTFE or PTFE containing a fibrous stiffening agent, said circuit-bearing sheets being joined in fixed relative positions by means of separating layers of a adhesive unsintered tetrafluoroethylene resin.

Abstract: A system for indicating occupancy of track sections in an interlocking area is disclosed comprising a multicomputer system which is assigned to several track circuits and processes the "unoccupied" or "occupied" indications of these track circuits. The multicomputer system, which is of a fail-safe design, also checks the operation of the associated track circuits and transfers an "unoccupied" or "occupied" indication of an associated track section to the interlocking station only if the test of this track circuit was positive. Any failures detected are also signaled to the interlocking station.

Abstract: Tetrafluoroethylene fine powder resins are described which have surprisingly high extrusion pressures and molecular weights which make them useful in post-paste extruded stretching operations. The resins are made by using a manganese triacetate/selected reducing agent polymerization initiator and controlling its rate of addition.

Abstract: A claw hammer having a protective cushion attached to the hammer head so that during normal usage it is in a resting position which will not interfere with the nail driving (or pounding) function of the hammer but at least a portion of the protective cushion is movable into a working position over the bell end of the hammer in order to prevent or minimize damage to the nail bearing surface when the claw end is used for nail pulling. The means facilitating movement of at least a portion of the protective cushion may be either a slide mechanism or a pivot point, such as a hinge, fold or bend. The protective cushion may be made of leather, rubber, synthetic rubber, plastic or other materials.

Abstract: It has been discovered that if a selected water-soluble aluminum, magnesium or zinc salt of a monovalent anion is added to an aqueous dispersion of a non-melt-fabricable tetrafluoroethylene polymer wherein the dispersion has a pH of 4 or less, the resulting dispersion will flow well on a woven fabric substrate, such as a woven glass fiber fabric, and will fill and cover the interstices of the weave without the necessity of having filler particles present.

Abstract: An arrangement enabling continuous control of vehicles on a track divided into individual areas comprises at least one track-conductor loop associated with the track in each of the areas having N transpositions therein, where N is an integer greater than two, the loop communicating data between the vehicles and a fixed control station by being coupled at opposite ends thereof to a different one of two supply units coupled to the control station and by being inductively coupled to communicating equipment on the vehicles. The one loop further comprises coupling elements disposed intermediate adjacent ones of the N transpositions to subdivide the loop into N track-conductor loops.