Abstract: An electric motor is wound with redundant sets of windings which are energized by independent electric circuits to enable operation of the motor even in the presence of a failure of a winding and a failure of an energization circuit. The motor may be of the permanent magnet form with electronic switching of the winding currents in lieu of switching via a commutator, known as a brushless DC motor, in which case separate sensing devices, such as Hall effect devices, are employed with each winding set and energization circuit for sensing the relative position between the moving and stationary members of the motor. The sets of windings, when placed on the stator, are physically spaced apart so as to minimize magnetic coupling therebetween.

Abstract: The present invention relates to a semi-additive or full-additive process for producing printed circuit or conductor boards having improved electrical resistance in which the coating of adhesive medium exposed between the trains of conductors is removed or partially removed without corroding the base material or copper of the conductor trains by a treatment with an alkaline permanganate or chromic acid solution and suitable washing steps carried out subsequently.

Abstract: An improved process for removing resin smeared on an interior wall of a hole in a resinous substrate and/or adhesion promoting the substrate which comprises: (a) contacting the substrate with an alkaline permanganate treating solution having a pH between about 11 and about 13 and an elevated temperature for a time period sufficient to remove the resin smear; (b) neutralizing essentially all manganese residue on the substrate; (c) contacting the substrate with an alkaline hydroxide etchant to remove the balance of manganese residue on the substrate. A metal such as copper subsequently may be electrolessly deposited in a more efficient and easily controlled manner on the resin substrate in the formation of a wire scribed circuit board or multilayer printed circuit board. In addition to resin smear removal, the process results in an improved bond between copper and the hole wall.

Abstract: A method of rapidly relieving stress in an extruded or molded polymer article is disclosed. The method can be used in the preparation of printed circuit boards. An article comprised of the polymer is exposed to electromagnetic radiation, for a time period sufficient to absorb enough energy to stress relieve the polymer against stress cracking therein. Exposure occurs at one or more ranges of frequencies which are capable of being absorbed by the polymer and which are effective for stress relieving without or substantially without causing heat induced softening or flowing of the polymer. The electromagnetic radiation is selected from the ranges of infrared, microwave or ultraviolet radiation.

Abstract: An annular illuminator comprising a spheric mirror, an elliptic mirror and a circular cylindric mirror. Flux received directly from the source is reflected by the elliptic mirror and then by the cylindric mirror. Flux not directed initially toward the elliptic mirror is first reflected by the spheric mirror and then by the elliptic and cylindric mirrors.

Abstract: A bearing structure for use in a linear motor or actuator including only a single guide rod in combination with a freely moving ball bearing. When used in a permanent magnet motor, the magnetic flux of the motor is used to preload the ball bearing to maintain a relatively constant bearing loading and to maintain the ball bearing in position.

Abstract: The metallic surfaces of plating equipment in use during electroless copper deposition, such as vessels, racks supporting substrates being plated, plumbing, and the like are rendered substantially resistant to electroless copper deposition for extended periods by initially imposing on such equipment surfaces an electrical potential more positive than the mixed potential of the electroless copper solution and sufficiently positive to resist electroless deposition, electrolessly depositing copper on the substrate being plated, and while depositing such copper maintaining on the equipment surface a potential sufficiently positive to resist the formation of adherent electroless copper deposits.

Abstract: A method for producing printed circuit boards with holes having walls provided with a metal coating on base material provided with an adhesive layer which, in turn, is covered by a masking foil composed of plastic material or metal. Following the preparation of the pattern of holes and prior to the removal of the masking foil, the layer of adhesive coating is removed at the edges of the holes by chemical action, so that an annular zone free of adhesive is formed underneath the masking foil. The masking foil is subsequently removed and the metallization of the pattern of conductors and walls of the holes is produced by currentless deposition alone or combined with galvanic precipitation.

Abstract: A linear DC permanent magnet motor comprising a wound member having a plurality of windings wound on a slotted magnetic structure and a field member movable relative to said wound member, the field comprising permanent magnet means for developing a magnetic field and means for energizing with DC current at least some of the windings, the magnetic field of said permanent magnet means interacting with the energized windings causing said field member to move relative to said wound member. The motor also comprises support means for maintaining air gaps between the wound member and the field member.

Abstract: A four quadrant control system for a brushless D.C. motor wherein the windings are energized via a drive switching circuit in a bridge configuration and the switching circuit is in turn controlled by a read-only memory. Pulse-width modulation control signals and position signals are supplied to the read-only memory as addresses together with other control signals. The system operates in a regenerative mode when changing direction and automatically makes a smooth transition into a motoring mode when the back EMF of the motor is no longer large enough to satisfy the requirements of the current loop.

Abstract: A unitary fan and drive assembly is formed by means of a disc-shaped plate having a set of fan blades disposed along the periphery of the plate. A compact shape is provided by forming the drive with a rotatable member that is nested within a central recess of the plate. An electric drive is conveniently implemented by an electric motor wherein the rotatable motor member has fan blades disposed along the periphery and wherein the stationary motor member includes a low-profile annular array enclosing an assembly for electrically energizing the motor.

Abstract: A method of rapidly relieving stress in an article comprised of a sulfone polymer is disclosed. The method can be used in the preparation of printed circuit boards. An article comprised of a sulfone polymer is exposed to electromagnetic radiation, for a time period sufficient to absorb enough energy to stress relieve the sulfone polymer against stress cracking therein. Exposure occurs at one or more ranges of frequencies which are capable of being absorbed by the sulfone polymer and which are effective for stress relieving without or substantially without causing heat induced softening or flowing of the sulfone polymer. The electromagnetic radiation is selected from the ranges of infrared, microwave and ultraviolet radiation.

Abstract: A process for forming a circuit board having rigid and flexible areas which includes the steps of severing an area corresponding to the board area which is to be flexible, from a rigid layer material, leaving the severed rigid layer area in place coplanar and contiguous with the remainder of the rigid layer material, laminating a covering layer to one surface of said rigid material and said rigid layer area, laminating a flexible layer material to the other surface of the rigid material without lamination to the surface of the rigid layer area and, after said circuit board has been completed, severing said covering layer around said severed rigid layer area and removing said severed covering layer and said severed rigid layer area from said board.

Abstract: Molded laminates useful in the preparation of electrically conductive panels are provided by a method comprising providing an article comprising a metal carrier or support layer, at least one insulating layer and a copper outer layer, the carrier having a plurality of perforations therethrough which are substantially filled with the insulating material, and compressing the layered article to produce a molded laminate. In other embodiments, the method comprises the further steps of forming a hole through at least some of the filled perforations, and, if desired, sensitizing the walls of the holes to electroless metal deposition and depositing a layer of metal thereon. Articles produced by the methods of this invention are also provided.

Abstract: An aspherical surface generating method and apparatus which optimizes the path of a moving cutting tool tip to fit a given aspherical surface of revolution to be cut on a rotating work piece engaged by the moving tip. The apparatus is a modified spherical generator, the modifications and control of which adapt it to continuously match the curvature of the path of the moving cutting tool tip to that of the given aspherical surface of revolution by adjusting the dynamic machine center in the direction of the evolute of the curve, i.e. along the locus of the radius of curvature of the given surface at the tool tip.

Abstract: An armature disc for an axial air-gap, direct current electric motor in which the armature consists of two half turn metal discs laminated to the opposite surfaces of an expoxy resin impregnated laminate disc with the half turn of the one disc joined to the mating half turn of the other disc at the mating surface at the disc I.D. and O.D. The resin disc extends from the I.D. of the half turn discs across the commutator area of the armature at the armature disc I.D. and terminates at or adjacent to the O.D. of such commutator area. The half turns outward of said O.D. may be air spaced or laminated to the opposite surfaces of an epoxy resin impregnated spacer disc.

Abstract: An annular illuminator comprising a spheric mirror, an elliptic mirror and a circular cylindric mirror. Flux received directly from the source is reflected by the elliptic mirror and then by the cylindric mirror. Flux not directed initially toward the elliptic mirror is first reflected by the spheric mirror and then by the elliptic and cylindric mirrors.

Abstract: Device to control the speed of an electric motor from a pneumatic pedal, characterized in that it includes an element deformable with the pressure controlled by the pneumatic pedal, an element of magnetic material forming a mechanical unit with the element deformable with the pressure and capable of modifying the inductance of a coil incorporated into an electronic control circuit for the current of the electric motor the speed of which is to be controlled.

Abstract: A device for position control including a first generator for delivering first and second identical signals dephased to each other by 90.degree.. A position pickup having two inputs connected to the first and second signals and an output for delivering a measurement signal whose phase is representative of the actual angular position of the component part to be controlled. A second generator for receiving a digital binary word instruction and for delivering an instructional signal of the same frequency as the first and second signals and having a phase representative of the desired angular position of the component part. A deviation signal generator connected to the output of the angular position pickup and the second generator for delivering a deviation signal representative of the dephasing between the measurement and instruction signals and a control device for controlling the angular position of the component as a function of the deviation signal.

Abstract: The heat shock resistance of plated through holes in printed circuit assemblies is significantly increased by using as the through hole plating a special multi-layered arrangement comprising at least two layers of an electrically conductive metal in combination with at least one intermediate layer of a different electrically conductive metal. In preferred embodiments, the through hole plating comprises at least two layers of a stressed metal together with at least one intermediate layer of a metal having a stress in counteraction to that of one or more of the other metal layers. These through hole platings are capable of exposure to conditions of heat shock, such as encountered during high temperature soldering, without developing cracks resulting in breaks in the conducting pathways and failures.