Abstract: An electro-optical device including a chiral nematic liquid crystal disposed between flat plates treated to weakly enforce molecular orientation along one preferred direction parallel to the plates. The plates are spaced by a distance small compared to the pitch of the helix typical in a bulk of the material, or the helix compensated by additives to ensure the equivalent situation. By an externally applied electric field the liquid crystal molecular orientation is rotated in a plane parallel to the plates away from the preferred orientation an angle the sign and size of which depends on the sign and magnitude of the field. The optical axis of the liquid crystal, oriented along the molecular orientation, is thus controlled by the external electric field in such a way as to make a linear light valve or other electro-optical device.

Abstract: A position controlled proportional directional control valve has a main control piston for controlling flow between passages to a pump, a tank, and to passages which may be connected to an operative device, such as a hydraulic motor. The main control piston may be moved in one direction by an operating piston slidably disposed in a centring flange which serves as a mechanical stop for movement of the main control piston in the opposite direction. Acting on the end of the main control piston opposite the operating piston is a centring piston having one end in a pilot control chamber, and which may urge the main control piston against the centring flange either by pressure fluid in the chamber, or upon failure of pressure, by the spring in the chamber. A pilot control valve, under the control of an electrical magnet, moves proportionally to the current in the electrical magnet, to admit fluid under pressure from a pump passage into the pilot control chamber.

Abstract: The improved method of melting a metal, especially cast iron, in a cokeless cupola furnace includes the step of injecting at least one case product quality improving and stabilizing substance into a space between the grate and the burners. The quality improving and stabilizing substance can be refining substance and a nuclear-enriching substance of the type used in code-fired cupola furnaces including nitrogen-containing substances such as ammonia and hydrazine and halogen-containing substances. A suitable apparatus for performing the improved process is also described having a downwardly direct lance for injection of the quality improving and stabilizing substance with an upwardly-directed mouth portion for forming an upwardly directed jet inserted through a furnace wall in a throughgoing guideway.

Abstract: A proportional valve comprises two electrically actuated proportional throttle valves, each having an outlet connected to a non-return valve, to each of which a seat valve is connected, each seat valve being pilot-controlled by one of the proportional throttle valves; the electric actuation of the proportional throttle valves proportionally controls and regulates the functions of a hydraulic cylinder. The two throttle valves and the two seat valves are mounted on a housing block which has a planar face at which are connections to a pressure line, a tank line and working lines.

Abstract: Device for the pressing of sheets during folding, including a first roller (2a) and a second roller (2b) which are positioned opposite each other and have rotation axes (3a, 3b) which are parallel to each other, and first permanent magnets (13a) engaged to the first roller (2a) and second permanent magnets (13b) engaged to the second roller (2b), the first permanent magnets (13a) and the second permanent magnets (13b) having opposite polarities facing each other. The process consists in applying mutual approach forces to the rollers which decrease as the distance between the same rollers increases.

Abstract: The throttle-part of the valve comprises a two-way seat valve with a follow-up throttle valve (8), which is driven by a differential guide piston (12) and an edge control system (20). The guide piston is pressurized via a pressure-spring (16) in a pressure-spring compartment in the direction of the closed position of the edge control system. The drive is effected via a pilot line A which pressurizes or depressurizes the pressure-spring compartment (18) via a proportional directional control valve (6), while the position of the guide piston (12) is determined by an inductive displacement transducer.

Abstract: A slide plate for a metallurgical vessel slide gate valve may include a ceramic plate, held by a binder, preferably cement, in a frame. The plate and frame combination is held by frictional force and without mortar in a plate holder. The frame is provided with an outcrimping having a wedge-like configuration tapering from the upper edge to the lower edge of the frame over at least a portion of its circumference. The plate holder is equipped in its area facing the outcrimping with a nondeforming and abrasion resistant clamping rail extending from the bottom to the upper edge. The mortar bed connecting the plate to the frame is recessed in the area of the outcrimping and the cavity formed between the outcrimping and the mortar bed is filled at least in part with a plastically or elastically deformable insert. The rail-like projection may be a profile rod, such as a round rod, positively held in the plate holder and may exhibit an undercut.

Abstract: Device for screwing and unscrewing screws, bolts and nuts comprising an electric motor (2), a flywheel (14) fixed on an auxiliary shaft (5) connected to the output shaft of the electric motor by means of a pair of pinions (3, 4) made of elastic plastic material like polyurethane and a wrench (9) connectable to said flywheel by way of projecting teeth (15, 16) and moving axially in relation to said flywheel by way of an elastic member (11).

Abstract: The main control piston (8) is controlled hydraulically by pilot control slide valves, operated in each case via two control magnets (4, 6) with force build-up proportional to the control current. In the case of failure of the electrical activation, the valve is always positioned in the center position by pressure centering and in the case of failure of the pilot control pressure it is positioned in the center position by spring centering.

Abstract: A sliding gate valve for metallurgical vessels, such as pouring ladles, is disclosed. The sliding gate valve may include a slide gate housing fastenable to a melt-containing vessel. A heat-resistant closure plate may be held stationary by a movable slide plate pressing against the closure plate. The slide plate may be supported in a frame having two sets of rollers. The frame may be connected to a drive, for example a hydraulic or pneumatic drive. An aperture may be provided in the housing bottom for passage of the frame rollers therethrough. The distance corresponding to the axial spacing between the sets of rollers is equivalent to the distance corresponding to the axial spacing between side apertures of the bottom aperture. The axial spacing between the rollers corresponds to the axial spacing between the side apertures to allow for the simultaneous passage of both sets of rollers through the side apertures.

Abstract: An electrical contact comprising a male element and a female element in which the male element is mounted for sliding with a tight fit, an air chamber being formed between an end of the male element and a bottom of the female element, the male and female elements being at least partially made from a porous material impregnated with an aqueous solution charged with submicron metal particles.

Abstract: An electronic circuit tester according to the invention comprises: a connection board for connection with each of the terminals of the circuit to be tested; n boards (16), called electronic pins, comprising signal shaping means each of which is connected to an input of the connection board; a single test vector memory unit (17) containing all the test vectors for the circuit and from the circuit, those vectors transiting through said electronic pins; a central processing unit (10) for managing the system and the external links; in which the management of the vector memory is made alternatively by a memory management unit (22 ) connected independently from the other tester units to the central processing unit (10) or by an address processor (23) asynchronously operating with respect to the central processing unit.