Abstract: In a printed circuit board pair, each of the printed circuit boards having a contact region with contact elements, a contact-making system includes a first circuit board having three-dimensionally structured contact elements and a second circuit board also having three-dimensionally structured contact elements structured complementarily with respect to the contact elements of the first circuit board for positioning the two boards together. The contact elements of the first board reciprocally electrically contact the contact elements of the second board. The configuration ensures a high positioning accuracy of the two contact regions with respect to one another. A mask having cutouts for contact elements of the two boards can be provided. Such contact element positioning using the conductor track pattern and being independent of a contact-making housing has the advantage that the positioning accuracy is unaffected by tolerances between the conductor track pattern and the contact-making housing.

Abstract: In order, in the context of making contact between two printed circuit boards (2, 4), to ensure a high positioning accuracy of their two contact regions (8) with respect to one another, the two contact regions (8) are three-dimensionally structured complementarily with respect to one another. A mask (12) having cutouts (14) for contact elements (10) of the two printed circuit boards (2, 4) is preferably provided. This positioning using the conductor track pattern and independently of a contact-making housing (26) has the advantage that the positioning accuracy is unaffected by tolerances between the conductor track pattern and the contact-making housing (26).

Abstract: The invention relates to a method which enables zones (10, 11) of a printed circuit (6) to be precisely and quickly exposed, both on the conductors (3) and to the side of these.Work is carried out on a blank provided with an insulating coating (4, 5) which may cover its entire surface. The coating is acted upon the zones (10, 11) to be exposed by means of a machining head having one or more laser beams and being controlled by a computer which receives the coordinates of the zones. The power of the beam is modulated differently on the conductors (3) and to the side of them, just as it is to make holes in the circuit or cut it along its periphery.The invention applies to the production of flexible printed circuits.

Abstract: A fixture for removably fixing a seat to the bowl or pan of a water closet comprises upwardly projecting studs secured to the water closet pan by bolts extending through holes in the pan and having washers and nuts on their lower ends. The studs are received in downwardly opening sockets provided in the seat to resist forces tending to move the seat horizontally relative to the pan. Permanent magnets in the sockets act between the seat and pan to resist upward movement of the seat relative to the pan.