Abstract: A burn-in board construction mounts and provides operational signals to circuit packages, for example, digital devices in an environmental stress operation such as in an oven/chamber for dynamic burn-in. Each of the circuit packages has connections to circuits and which connections are connected to conductors on the burn-in board. At least one auxiliary board is mounted on a main burn-in board and carries contacts to double the number of test connections for digital devices on such burn-in board without changing the basic mounting or environmental chamber construction. The construction permits two 128 pin driver/receiver boards of standard design to be connected to each burn-in board module. This permits coupling several hundred driver connections to a single burn-in board while still utilizing standard connectors as the interconnects.

Abstract: In a method of detecting the deflection of the blades 13 of a helicopter rotor as it rotates, a beam 14 of radiation from a transmitter/receiver 11 encounters the tips of the rotating blades which send reflected signals to the receiver. The phase difference due to deflection of the blade tip can be used to give a measure of the deflection of each blade, and that can be displayed graphically as shown in FIGS. 7-10 for the various blades at various speeds. In a related method of measuring deflections of the blades 111 for a tail rotor, a laser beam transmitter 16 in FIG. 14 has its reflected beam 122, 123 from an undeflected blade 111 or a deflected blade 111' received by a particular receiver in a linear array 119 of receivers so that the particular receiver gives an indication of the amount of deflection.

Abstract: This invention relates to a system for strictly positioning along an axis an object such as a wafer of semi-conducting material during a process of constructing integrated circuits, wherein it comprises:means for controlling the drive means for causing the carriage to make a displacement of acquisition of which the amplitude is at least equal to the step of the second optical grating;a generator generating, during said displacement of acquisition, a periodic reference signal, of period equal to the step of said second grating;multiplication means for forming the product of said period reference signal and of the signal actually delivered by said photoelectric sensor;means for summing the signal formed by the succession of said products;calculating means for determining the possible offset existing between said optical gratings; andmeans controlling the drive means to bring said optical gratings into strict alignment.

Abstract: A linear guiding system incorporating rolling members, having a central element and a peripheral element connected to each other by at least one pair of rolling member assemblies associated with blocks fixed on the peripheral element by means of screws, and disposed opposite one another on either side of the central element. There is a device for adjusting the pressure exerted by the rolling members on the central element when the fixing screws are loosened. The pressure adjusting device is outside of the guiding system and is adapted to be temporarily fast with the blocks, and comprises apparatus for measuring the pressure exerted by the rolling members on the central element.

Abstract: A detector for checking the symmetry of a helicopter rotor while it is rotating has a scanner (11) which scans vertically a field of view (15) and the view is interrupted by a vertical strip on the blade tip (16). A slot (18) in the strip gives a characteristic signal as at (L.sub.2). The position of the signal (L.sub.2) in a scanning cycle gives an indication of the height of the blade tip and also the circumferential spacing between blades.

Abstract: A three dimensional graphics tablet for determining the three dimensional coordinates of points on an object placed on a supporting plane. The apparatus includes an articulated arm having at least two link elements connecting a contacting tip element to the support for rotational movement about a plurality of mutually angulated axes. By means of the arm articulation, the contacting tip element can be moved to arbitrary locations within a defined volume. Potentiometers are provided for measuring each of the angles of rotation about the mutually angulated axes. These potentiometers generate signals which collectively determine the coordinates of the location of the tip element. Embodiments are disclosed having three and four degrees of freedom and a portable embodiment including a clamp or bracket are disclosed.

Abstract: A three dimensional graphics tablet for determining the three dimensional coordinates of points on an object placed on a supporting plane. The apparatus includes an articulated arm having at least two link elements connecting a contacting tip element to the support for rotational movement about a plurality of mutually angulated axes. By means of the arm articulation, the contacting tip element can be moved to arbitrary locations within a defined volume. Potentiometers are provided for measuring each of the angles of rotation about the mutually angulated axes. These potentiometers generate signals which collectively determine the coordinates of the location of the tip element. Embodiments are disclosed having three and four degrees of freedom.