Abstract: Several unique features of a key switch housing and plunger are disclosed which may be employed to provide a keyboard having improved noise and feel characteristics. A system of key plunger up-stops is used to reduce the noise produced by key return while preventing removal of the plunger from the chimney of the switch housing. The system comprises a pair of relatively weak and resilient up-stops which have a relatively small contact area which act to restrict upward movement of the keycap/plunger combination during normal operation and a pair of relatively strong and rigid up-stops which do not contact the switch housing during normal keyboard use, but which prevent the pull-out of the key switch plunger from the chimney of the key switch housing. An additional feature disclosed is a unique key switch housing and plunger design which minimizes key wobble while providing smooth key action.

Abstract: A light pipe used for backlighting liquid crystal displays has a planar front surface and a stair-stepped or faceted back surface. Light is injected from the ends of the light pipe from cold- or hot-cathode, apertured, fluorescent lamps. The cold-cathode lamps are preferably insulated to raise their operating temperature. The back surface has a series of planar portions parallel to the front surface connected by facets, which are angled so that the injected light reflects off the facets and through the front surface. A reflector having a planar, highly reflective, highly scattering surface or a sawtoothed or grooved upper surface in located adjacent to and parallel with the light pipe back surface to reflect light escaping from the back surface back through the light pipe to exit the front surface. The axis of grooves is preferably slightly skewed from the facet axis to reduce moire pattern development.

Abstract: An automatic switch actuator is disclosed which may be used to test press-to-actuate type switches--for example, the key actuated switches of a computer keyboard. In the illustrated embodiment of the invention, a system of electrically operated valves are used to apply four different fluid pressures to selected pistons of an array of pneumatic cylinders. Each cylinder is mechanically connected to a plunger which is oriented so as to contact a selected key in an array of keys (i.e., a keyboard).

Abstract: A process is disclosed from mounting through-hole components having closely-spaced electrical leads to a printed board (PCB) using solder paste. The process comprises applying conventional solder paste to alternating through-holes in an array of through-holes, inserting the through-hole component, applying solder paste to the remaining through holes on the opposite side of the circuit board and subsequently melting the solder (typically in a reflow oven) to form both a mechanical and an electrical connection of the through-hole component to the printed wiring board. Practice of this process alleviates the problem for solder bridges forming between adjacent leads or through-holes. Moreover, this process allows a PCB to be equipped with both surface mount and through-hole components without the need for a separate wave soldering operation to secure the through-hole devices.

Abstract: An improvement to a conveyor system is disclosed which comprises a system of magnets and removable ferromagnetic strips which may be easily attached to Printed Circuit Assemblies (PCA's). In one preferred embodiment, the magnets are mounted to brackets which are bolted to the conveyor chain. These magnet assemblies act to secure the PCA's which have clip-on stiffeners affixed to their leading edges. The PCA's are thereby prevented from sliding on the conveyor chain as it moves up and down inclines. The likelihood of damage to PCA's on the conveyor system is thus reduced. The PCA's are released from the magnet assemblies by the shearing action produced by the conveyor chain as it rounds the return roller at the end of the coveyor line.

Abstract: A small computer system interface (SCSI) bus between a host system and one or more peripheral devices is terminated at one end of the SCSI bus, proximal to the host system, and at the other end of the SCSI bus by a loopback terminator. The loopback terminator is formed by a signal board with one connector that is adapted for receiving signals from the SCSI bus, a multiconductor cable having a pair of ends, a pair of cable connectors, each of which is adapted to mate with respective ends of the multiconductor cable, and a terminator coupled to one of the cable connectors. One or more of the peripheral devices are connected to the multiconductor cable via respective nodes, and the multiconductor cable is routed back to the signal board coupled to form a "loop" between the pair of cable connectors.

Abstract: A fast logic system for decoding addresses for the purpose of designating areas of memory as non-cacheable is disclosed. The logic system is based on a programmable array logic having as inputs selected address lines, certain switch settings, and software-selectable diagnostic settings.

Abstract: A support apparatus for a portable personal computer expansion unit provides a plurality of interlocking ribs on the mating surfaces of the portable personal computer and expansion unit, and a latch mechanism to releasably lock the mating surface of the computer expansion unit to the mating surface of the portable personal computer.

Abstract: A novel solder pad configuration for printed circuit boards is disclosed which is resistant to solder occlusion upon wave soldering. On the solder side of the circuit board the solder pad is substantially C-shaped and partially surrounds a non-plated through-hole. Via holes prvide electrical connection between the pad on the solder side of the board and the corresponding pad on the component side of the circuit boards. The invention is particularly applicable to the chassis ground mounting holes of PCB's.

Abstract: A printed wiring board is disclosed which has one or more solder pads of special configuration which receive and contain excess solder which might otherwise bridge adjacent downstream leads of a component having closely spaced leads when the component is mounted to the printed circuit board in a wave-soldering process. The special solder pad configuration may be viewed as an extra solder pad (a "robber pad") at the downstream end of a linear array of solder pads which is connected to the adjacent upstream solder pad by a solder-wettable bridge.