Abstract: A brake circuit for a universal motor having an armature and a field winding normally connected in series therewith, the circuit including switch means operable to disconnect the power source and electrically connect the armature in series with the field winding and a brake resistor, with voltage limiting means in parallel with the field winding. The voltage limiting means include biasing diodes for maintaining the voltage across the field generally constant, resulting in a more even deceleration rate and a lower total brake time.

Abstract: A centrifuge rotor assembly having a resilient liner with at least two separate chambers. Fluid communication between the separate chambers is automatically controlled in response to centrifugation operation of the rotor. When the rotor is stationary, the liner assumes a first position within the rotor where an annular chamber is sealed from a central chamber. When a fluid sample is placed within the liner of the rotor and the rotor is subjected to centrifugation, the centrifugally induced forces of the fluid mixture shift the liner to a second position, opening the sealed condition between the central and annular chambers to permit fluid communication between the respective chambers. When the centrifugation operation has been completed and the rotor returns to its stationary position, the inherent resilient structural characteristics of the liner automatically re-establish the seal between the respective chambers.

Abstract: A rotor having a plurality of swinging carriers designed to receive specimen samples for subjection to centrifugation. The carriers are pivotally mounted to a rotor frame in such a manner that the generally flat support faces of each of the carriers assumes a parallel orientation with respect to the rotational axis of the rotor during operational speeds of the rotor. When the rotor is not operating, the support surfaces of each of the carriers assumes the perpendicular or acute angle orientation with respect to the rotational axis of the rotor. In order to overcome any resistive frictional forces which may be generated at the interface between the rotor frame and the pivoting carrier, the pivot axis of the carrier is shifted from the central or center of gravity plane of the carrier to ensure that the support surface of the carrier will positively assume its proper parallel orientation with the rotor spin axis.

Abstract: A hermetic glass seal to provide the final seal for the fill ports in the glass walls of a display device such as a liquid crystal display. The seal utilizes a glass bead sandwiched between a metal cover and a polymeric separator.

Abstract: A pivotal carrier for use in centrifuge rotors wherein the ends of the rotor carriers are adjustable to vary the supporting or receiving surface area in the carrier to accommodate various sized tube racks which may be used in the centrifuge rotor. Holding members in opposite ends of each carrier are movable to a plurality of positions to symmetrically position the tube rack within the carrier to maintain dynamic rotor balance.

Abstract: A gas discharge display device for exhibiting an analog value in a sealed envelope having a viewing window with a plurality of linear cathode segments arranged in succession to form a row or column capable of exhibiting a glow discharge. The cathodes are arranged in groups within the sealed envelope with a separate anode electrode in operative relationship with each of the groups of cathodes. Alternate ones of the anode electrodes are activated simultaneously in alternating sequence, so that the time duration of cathode glow exhibited on each cathode segment is increased to provide a significant increase in the intensity of the bar graph display. The intensity of the bar graph may be decreased to accommodate a surrounding environment by reducing the on time for each cathode segment.

Abstract: A flat screen, electrically controlled, reflective display device is provided that utilizes a very thin layer of a positive dielectric anisotropy liquid crystalline material of the nematic type. The selected liquid crystal material is one whose optical phase shift transmission is a sensitive function of the electric field within it, allowing controlled optical transmission in conjunction with an optical circular polarizer. The nematic material is placed in a very thin layer in a flat-sided cell between transparent planar cell wall elements that accurately define the thickness of the nematic layer. Birefringence of the nematic liquid crystal is controlled by voltages applied to interleave arrays of alternate parallel electrodes coated on the inner surface of only one of the transparent cell elements. The invention includes novel means for holding constant and uniform the thickness of the thin nematic layer and for reducing undesired parallax and multiple image effects.

Abstract: An air driven centrifuge which utilizes a stator with a floating stator pad for alleviating excessive vibration of the rotor associated with critical rotating speeds. The floating stator pad incorporates means for increasing the friction between the pad and the stator in order to increase the ability of the stator pad to provide greater dampening of the rotor for improving the smoothness and stability of its operation.

Abstract: A centrifuge rotor having a sealing element which automatically controls in response to the centrifugation operation the fluid communication between separate fluid mixture chambers within the rotor. The sealing element is situated within the rotor above an annular and an inner chamber used for containing a fluid mixture. When the rotor is assembled and stationary, the sealing element establishes a seal between the respective chambers. During the rotation of the rotor in a centrifuge, the centrifugally induced pressure exerted by the fluid mixture moves the sealing element, releasing the seal between the respective chambers and allowing fluid communication between the chambers. As the rotor returns to a stationary position and the centrifugally induced pressure of the fluid mixture subsides, the sealing element automatically re-establishes the seal between the respective chambers.

Abstract: In a table top centrifuge of the type including a rotor and a housing defining a chamber for the rotor, the housing having a removable cover therefor, there is disclosed an improvement wherein the cover has first and second passageways extending entirely therethrough, from the center and periphery, respectively, thereof to spaced locations on one of the outer surfaces thereof to define inlet and outlet ports, respectively. A refrigeration unit is provided having a cold air outlet port and a warm air inlet port at spaced locations on one of the outer surfaces thereof, the spacing between and orientation of the centrifuge and refrigeration unit inlet and outlet ports being such that positioning of the one outer surfaces of the centrifuge and refrigeration units in contact with each other aligns the outlet and inlet ports of the refrigeration unit with the inlet and outlet ports, respectively, of the centrifuge.

Abstract: This invention provides a snap-in terminal for electrical connection between an external conductor and a conductive film deposited on a nonconductive substrate. The terminal is stamped from a flat sheet of resilient conductive material and comprises a center position having a forward extension to which the external conductor may be attached and a rearward extension curved downward for establishing electrical contact with the film on the substrate, and a plurality of legs extending outward from the center portion and bent about 90.degree. downward from the center portion, each leg having at its terminus a tab. The terminal is installed by inserting the legs into a slot in the substrate contiguous with the film. The tabs deflect to fit within the restricted space of the slot and then recover their original position as they emerge from the slot at the bottom of the substrate, thereby securing the terminal to the substrate.

Abstract: An improved apparatus and method for braking the rotation of a centrifuge rotor is disclosed comprising magnet means operable in a first position wherein substantially no eddy currents are induced in a rotating rotor made of electrically conductive material by the magnetic flux of the magnet means and a second position wherein eddy currents are induced into the rotating rotor sufficiently to slow the rotor. In the preferred embodiment, the magnet means is movable by fluid pressure from the second position to the first position and movable by a bias force from the first position to the second position.

Abstract: An adjustable supporting arrangement used within the sample receiving cavity of a centrifuge rotor to hold and align a plurality of test tubes. The arragement is comprised of a series of similarly configured interface layers which can be variably arranged to accommodate different sized test tubes. A bracket member is utilized to retain the alignment of the various interface layers and hold them as a single unit for convenient movement into and out of the rotor cavity. Incorporated within the supporting arrangement is a separate cushion pad to receive the bottom ends of the test tubes. A uniquely designed divider plate can be placed within the supporting arrangement to partition the rotor cavity into two areas for receipt of two sets of test tubes in stacked relation.

Abstract: An adaptor for use in a centrifuge bucket for evenly distributing a number of cylindrical test tubes thereacross and for maximizing the number of test tubes positionable in the bucket. The adaptor comprises a thin, flat, disc-shaped plate having a diameter approximately equal to the inside diameter of the bucket and a plurality of separate, unconnected partitions made integral with and extending normal to one side of the plate, the partitions defining a plurality of cavities for receipt of the bases of the test tubes. The partitions support substantially less than the entire circumference of each tube and have lengths which are substantially less than the lengths of the tubes. A lifting tray and handle provide means for lifting the adaptor and test tubes from the rotor bucket.

Abstract: A vacuum seal for use in a continuous flow centrifuge apparatus for minimizing heat transfer from the vacuum bushing to the rotary transfer tube which is conducting the sample solution to the centrifuge rotor. An elongate, cylindrical sleeve surrounds the transfer tube, coaxial therewith and spaced therefrom, adjacent the upper end thereof, between the transfer tube and the vacuum bushing, the bushing creating an oil film around the transfer tube to provide the vacuum seal, the annulus formed between the inner surface of the sleeve and the outer surface of the transfer tube isolating the transfer tube from the heat created in the oil film.

Abstract: In a centrifuge rotor of the type including a yoke and an enclosure for the yoke, the enclosure being operatively connected to the yoke for rotation therewith, the enclosure comprising a wind shield physically connected to the bottom of the yoke and extending beneath the yoke and around the sides thereof and a lid being positionable over the yoke to engage the wind shield for completely enclosing the yoke, there is disclosed a method and means for retaining the lid in contact with the wind shield wherein the wind shield terminates in an upwardly facing circular lip and the cover terminates in a downwardly facing circular lip so that the lip of the lid engages the lip of the wind shield, there being no physical connection between the lid and the wind shield, the lid being retained in contact with the shield during rotation of the centrifuge rotor by the force created by the naturally-occurring low pressure within the enclosure, beneath the lid.

Abstract: In a swinging bucket centrifuge rotor of the type including a core with outwardly extending support arms having removable trunnion pins for supporting a plurality of bucket assemblies, each bucket assembly including a rotor bucket support having a pocket on opposite sides thereof for receiving the extremities of adjacent pins, there is disclosed an improvement wherein each of the arms has only a single hole formed in the outer end thereof, perpendicular to the longitudinal axis thereof, for receipt of a single trunnion pin including a central portion and acutely oriented opposite extremities, the opposite extremities of each trunnion pin extending outwardly from the arms towards and coaxial with the outwardly extending extremities of the pins of adjacent arms, and wherein the pockets in each support are cut into the sides thereof at an acute angle relative to the axis thereof.

Abstract: A rotor for a centrifuge including a symmetrically shaped rotor body adapted for rotation about its axis and including a suitable cavity for receipt of samples to be centrifuged. The rotor body is provided with means adapted to cooperate with a centrifuge driving means for rotating the rotor body abouts its axis for centrifuging liquid samples in the cavity. The rotor body is provided with an annular shoulder formed around the top of the rotor and surrounding the opening to the sample cavity, the shoulder having an inward facing surface adapted to receive a thin flexible disc having a bowed shape in the direction of the opening to the cavity so that the edge of the disc seats against the annular shoulder. In its preferred form the disc has a diameter greater than that of the annular space bounded by said shoulder and is bowed by a force against the center portion of the disc causing it to flex in the downward direction thereby assuming a "dish-shape" covering the opening to the cavity of the rotor body.

Abstract: A liquid crystal display cell comprising a pair of oppositely disposed glass plates having transparent conductive electrodes formed on the facing surfaces thereof, said glass plates being joined by a seal material along the outer periphery thereof, with the seal material having a small opening formed therein for filling the interior volume of the cell with a liquid crystal material. A barrier is provided internally of the cell having one end joined to the seal material adjacent one side of the fill opening and having its other end extending beyond the fill opening parallel to at least one side of the display cell. The barrier extends between the glass plates, being sealed thereto, and opens into the internal volume of the cell to provide a channel communicating between the fill opening and said internal volume.

Abstract: A composition and method of forming a seal in a liquid crystal display cell wherein planar glass plates are bonded together with a dispersion of fluorocarbon and an organosilane coupling agent to form a hermetically sealed cell wherein the seal does not react with the liquid crystal material.