Abstract: A block-like body including a cap plate and a pair of rigid plates of a common width and of different lengths substantially registered with said cap plate and disposed in mutually superimposed relation for defining a pair of adjacently related working surfaces arranged in mutually stepped alignment, and a sanding pad arranged in substantially covering relation with each of the working surfaces, each pad being characterized by a resiliently backed, rigidly supported strip of abrasively coated, flexible material having at least one end secured between a pair of said plates and a screw extended through said plates for releasably securing the plates against displacement relative to one another.

Abstract: A hollow post tube 12 is reciprocable on an anchor spike 14 to implement the placement and removal of a sign post. A striker plate 20 located on the bottom of the post tube may be repeatedly hammered down against a ground abutment plate 16 or up against an impact plate 18, both secured on the anchor spike, to drive the anchor spike into or out of the ground. Planar ears 22 secured to the spike below the ground abutment plate prevent the spike from turning in situ, and the post tube and impact plate are cooperably square in section to prevent the tube from rotating on the spike. A sign carrying cross bar 24 is removably mounted in the open upper end of the post tube by a releasable spring detent strap 36 rigidly secured to a mounting tube 34.

Abstract: A ground-based portable and collapsible structure comprises two similar rectangular plates hinged together and disposed in downwardly-diverging relationship with their hinge-remote edges engaging the bottoms of re-entrant slots opening from the upper edges of spaced and parallel bar means of inverted T-section disposed on the ground transverse to said plate edges. Each bar means may be an inverted T-section bar or two L-section bars secured to one another with their vertical webs mutually opposite and spaced, preferably by spindles on which spiked metal strips are mounted for pivotal movement between a first position wherein it is accommodated in said gap and a second position wherein it projects downwardly from the L-section bars, the two strips being offset one to each side of the median plane bisecting said gap and being maintained in such dispositions by spacers mounted on the spindles alongside the strips.

Abstract: A thin shell of hard plastic has a cavity within which a polyurethane foam is received. Each panel includes an upper, relatively straight-line edge, two side edges at substantially 90 degrees to the upper edge, and a lower, irregular edge having the appearance of a plurality of individual roofing shakes. The upper edge is canted upwardly for receipt within a groove in the underside of an upper overlapping panel. In addition, immediately adjacent the canted upper edge, there is a bandlike section through which roofing nails may be applied for securing the panel to the roof. The undersurface of each panel includes a stepped arrangement, not unlike that encountered in a roof constructed of individual shakes, which arrangement enables a pair of such panels to be fitted together with the top surface of one panel contacting the lower surface of another panel and forming a substantially parallel surface package for storage and shipment.

Abstract: This invention relates to a system for anchoring structural members, such as structures made of round and profiled tubes of steel, non-ferrous metal, light-alloy and plastics. The object of the system is for tubular members of any size and load-bearing capacity to be erected vertically on any ground, irrespective of the slope or gradient and unevenness.

Abstract: Each log is provided with a tongue on the upper surface and a rectilinear groove in the lower surface thereof. The edges of the tongue are beveled so that upon insertion into a rectilinear groove elongated expansion chambers will be defined to halt the propogation of drafts between the mating surfaces of adjacent log courses. A check groove is provided at the bottom of each groove in the bottom of the log for the purpose of releasing tension in the log as it dries while the top surfaces of the log are completely free of grooves to prevent any accumulation of moisture or dirt which would lead to early decay. The corner joints have a truncated triangular configuration with the tongue portion of one log extending into the tongue portion of the other log so that the actual joint is surrounded and protected from the weather by the raised tongues on the top of the logs.

Abstract: An assembly for mounting access flooring over a permanent surface is comprised of a plurality of supporting pedestals. Each pedestal carries an upper panel support plate and each plate has a plurality of precisely dimensioned indexing members rigidly fastened thereto, one of said members being precisely positioned adjacent each corner of the plate. Each of the floor panels is provided with a precisely dimensioned indexing member receiving aperture on the underside thereof adjacent each corner of the panel. Upon aligning and securing a small number of the pedestals over the permanent surface over which the access flooring is to be mounted, and mounting flooring panels on the aligned and affixed pedestals by firmly engaging the indexing members into the indexing member receiving apertures in the panels, the remainder of the pedestals and floor panels are self-aligned for easy mounting over the remainder of said permanent surface.

Abstract: A suspended ceiling panel assembly particularly where one side of the panel is a mirror. The assembly to be suspended from supports. On the panel is a hanger, and a locking member is pivotally joined to the hanger. The locking member has a stable position which allows it to be hung from the supports. The locking member is pivotable out of its stable position to a second stable position which allows the panel to be removed from the support.

Abstract: A clip for holding an insulating and/or fireproofing panel to the surface of a structural member such as an I-beam or the like. The panel may be coated on one side thereof with a suitable adhesive and the clip will assist in supporting the panel in intimate contact with the surface of the structural member during the setting or hardening of the adhesive. In instances where the panel is left uncoated with an adhesive, the clip is strategically spaced along the length of the structural member to maintain the panel in close contact with the structural member.

Abstract: A method for improving the thermic insulation of a metal building having a rigid frame structure comprised of metallic columns, beams, braces and rafters rigidly fixed to each other, to which sheet metal roof and wall panels are secured by metallic fasteners. A thick layer of insulating material is first placed on the inner surfaces of the roof and wall panels before they are secured to the rigid frame, and the insulating material is then pinched between said panels and the frame members. Then, insulating covers are glued in place on each of the members of the rigid frame to completely cover all exposed portions of such members within the building and under the layer of insulating material. The result is to reduce heat loss, and greatly alleviate the formation of condensate moisture within the building.

Abstract: A device for encasing coins in protective envelopes embodying a generally rectangularly contoured housing elevated at one end and stepped down intermediate its ends to provide a flat work surface offsetedly spaced below the elevated end, with insulation flatly superposed on the work surface thereof and heating coils embedded therein and encircling a centrally disposed coin receiving area. A generally rectangular forming member pivotally mounted to the elevated housing end and overlying and elevatable relative to the work surface.

Abstract: This disclosure relates to apparatus for applying screw-on caps to containers. The caps are fed down a chute and are engaged by the mouths of containers. Each cap, after it is engaged with the mouth of a container, is pressure-urged down onto the container in a position parallel to the path of movement of the container and is rotated in a screw-off direction. It then moves to a position where it is engaged by another friction device and another hold-down device where it is rotated in a screw-on direction.

Abstract: A sealing machine is disclosed of the type which applies closure caps to containers at extremely high speeds by moving filled containers successively through a cap feeding station, a cap applying station, and a cap sealing station. The machine is characterized by improvements in its several sections which permit it to operate effectively at increased speeds, and at the same time provide for an improved adjustability for differing package sizes. The adjustability provides for independently operable adjustments for the sealing chamber height and for the width and height of the side belts which move the containers through the sealing chamber. Additionally, an improved cap feed is described with a cap feeding star wheel and improved container guiding side belts are also disclosed.

Abstract: Method of and apparatus for wrapping reams of paper or the like in which the ream being wrapped is placed on an elevator mechanism at a lower level and raised by the elevator mechanism to an upper level. The elevator mechanism comprises a central support and two outboard supports extending endwise of the ream. The outboard supports are movable inwardly from an outer position wherein they are spaced outwardly from the central support. The outboard supports occupy their outer position as the ream is placed on the supports and while the ream is being raised. As the ream is raised, it engages a wrapper sheet and portions of the wrapper sheet fold down on the sides of the ream. When the ream is raised, underfolders move in under the ream from opposite sides of the ream to fold portions of the sheet in under the bottom of the ream.

Abstract: A pair of centrifugally movable shoes are pivotally mounted to a mower blade support. Drive bands are supported by the respective shoes and are positioned so as to be engageable with a source of rotational movement whereby such movement is translated to the blade by the bands, the shoes and the blade support. A brake band selectively engages the shoes to decelerate them thereby braking the blade. Additionally, engagement of the brake band with the shoes moves the latter in opposition to the centrifugal force applied to the shoes during rotation. This results in the drive bands being moved out of engagement with the rotational source.

Abstract: An improved fruit harvester, including a self-propelled main frame with means for grasping a fruit tree and inducing vibration in the fruit tree so that fruit will be caused to fall and a retractable collection surface which extends beneath the tree to gather the fruit as it falls. The gathered fruit is directed to either of two longitudinal conveyors disposed on each side of the main frame which transport the fruit to the rear of the harvester. A transversely mounted conveyor is disposed between the respective termination points of each of the longitudinal conveyors and is capable of selectively receiving fruit from either of the two longitudinal conveyors and depositing said fruit in either of two receptacles elevatably supported at the corners of the main frame of the harvester.

Abstract: In a spindle assembly of a spinning or twisting frame, the improvement consisting in inserting, between the stator and the rotor of the spindle assembly, braking members made of an antifriction material in the form of arcuate blocks or sectors which act also as spacers for the revolving members (usually spheres) which match the stator with the rotor.The device solves the problem of providing a braking action for providing the thread tension without problems of overheating the thread being spun.

Abstract: Self-twisting yarns are made by a system in which a strand twisting device is engaged with the strand and moves at strand speed to twist the oppositely-extending sections of the strand in opposite directions. The strand is brought together with another strand and released, enabling it to untwist and twist itself to the other strand. Various arrangements are disclosed for maximizing the distance between twist reversal nodes, for cabling plied yarns together, for strengthening the strands, for reducing the tensile stresses imposed on the strands and for producing unique products with non-uniform node spacing or unequal strand lengths between adjacent pairs of nodes.

Abstract: Fabrication techniques for making nickel boron stranded wire braze preforms are described. The techniques involve the provision of the wire material in a stranded form having a large surface to volume ratio. This general form consists of a plurality of fine wires, having the desired cross-sectional area, which may be twisted or braided to produce the preform.

Abstract: A method of making a chain generally consisting of forming at least two links integrally so that the two links are interlocked and are joined together and then severing the links along the joint to provide at least two separate, interlocked links.

Abstract: An active clearance control (ACC) for a turbofan engine is disclosed herein where the cross section of the external spray bars are fabricated in square or substantially square configurations.

Abstract: New and improved methods and means are described for the efficient, expeditious, economical, and safe conversion to usable form of almost all subsurface wave energy available within a predetermined annular region spanned by an array of submerged wave energy removing impellers mounted upon an annular outrigger surrounding and secured to a seagoing central platform. Maximal progressive inward attenuation of practically any state of the open sea is achieved over a very broad wave frequency band by buoyant, nonbuoyant, and neutrally buoyant impellers that function approximately as generalized simple pendulums whose natural frequencies fall at regular intervals throughout that frequency band. Optimal functioning of the impellers is achieved by assigning to their working members suitable degrees of omnidirectional response to water movement interial and drag forces, respectively.

Abstract: Process and system for recovery of energy from geothermal brines and other hot water sources by direct contact heat exchange between the brine or hot water, and a working fluid exiting the top of the heat transfer column is expanded through an expander to produce work. The discharge from the expander is cooled to condense working fluid which is separated in an accumulator from condensed water vapor present in the working fluid, and the condensed working fluid is pressurized and fed back to the heat transfer column. Uncondensible gas together with working fluid losses are vented from the accumulator. In order to decrease the amount of uncondensible vent gas from the accumulator, and the loss of working fluid therein, the hot water or brine feed to the heat transfer column is initially degassed as by flashing, the extent of degassing being controlled based on the concentration of uncondensibles in such hot water or brine feed.

Abstract: A method and an installation for the utilization of residual heat in pulp mills, where spent cooking liquor is evaporated with vapor in a multi-stage evaporator. The installation for carrying out the method comprises a number of evaporation steps connected in such a way, possibly by arranging several steps or groups of steps in parallel, that the outlet vapor from the last step or steps holds saturation pressure immediately below atmospheric pressure, a heat exchanger for condensation of the outlet vapor from the evaporation steps during evaporation of a fluid which, for the corresponding amount of heat, at the actual heat exchange temperature, has a markedly smaller volume than the outlet vapor, a turbine for expansion of the fluid vapor, a condenser for condensing the outlet vapor from the turbine, and a pump for increasing the pressure of the condensed fluid to a pressure suitable for return to the heat exchanger.

Abstract: A cryostat for maintaining an inventory of a liquefied cryogen including a vacuum jacketed reservoir (Dewar) containing heat shields in the vacuum jacket, the heat shields cooled to different temperatures and a cryogen recondenser cooled by a cryogenic refrigerator. Included in the cryostat is an access passage to place objects in the cryogen and to support the refrigerator, the access passage including means to remove the refrigerator without opening the liquid cryogen to ambient atmosphere.

Abstract: A swimming pool heating system which utilizes a heat pump that is used for heating heat transfer fluid which is circulated through the primary coil of a heat exchanger. The pool water is circulated through the secondary coil of the heat exchanger by means of a standard pool pump. Rather than heating all of the water which is handled by the pump, a system bypass line is connected to the pool outlet line and a diverter valve, which is located in the pool return line, is used to divert a portion of the circulated pool water to the heating system. A three-way regulator valve located in the system bypass line divides the diverted pool water, directing a selected portion of it to the heat exchanger and a selected portion of it to the pool return line in order to automatically control the heating effect the pool heater has on the heat transfer fluid, thereby keeping the discharge pressure of the heat pump relatively constant so that it operates in its most efficient range.

Abstract: A method and apparatus utilizing a hot gas defrost system wherein superheated gas from the system compressor outlet is conducted directly into the heat exchanger to be defrosted, by-passing the condenser and thermal expansion valve to effect removal of the frost and ice accumulation on the heat exchanger surface. A portion of the hot compressor discharge gas is conducted directly into an accumulator with the liquid refrigerant received from the heat exchanger to be defrosted, the liquid refrigerant resulting from the gaseous refrigerant being condensed in the heat exchanger as the ice is melted. The refrigerant condensed to a liquid during defrost is vaporized in the accumulator thereby providing a supply of gaseous refrigerant to the compressor suction line, said gaseous refrigerant being a combination of the non-condensed discharge gas conducted to the accumulator and the liquid refrigerant vaporized in the accumlator.

Abstract: Freezing and melting techniques are described for separating 1,3-butadiene from a mixture of four-carbon compounds by fractional freezing of the liquid mixture and by fractional melting thereof. It has been discovered that when a frozen four-carbon mixture (BB) containing about 36% 1,3-butadiene (BD) is initially frozen, the first frozen fraction of up to about 30% of the mixture is enriched about 80% over the feed sample while the filtrate is decreased in BD about 36%. A second fractional crystallization of the melt and of the filtrate shows continued enrichment and impoverishment as to BD content, respectively. It has also been discovered that when a solidly frozen BB mixture is slowly thawed and the melt is progressively removed, the melt becomes markedly enriched in BD. A continuous fractional crystallization process that uses these discoveries for producing BD at purities greater than 99% is described.

Abstract: A constant velocity joint having first and second rotatable bodies, at least one of the bodies being angularly and axially displaceable with respect to the other. An elongated member for transmitting torque between the bodies extends in its longitudinal direction transversely in a slot in one of the bodies and is connected to the other body. The member is slidable along and pivotable about its transverse axis in the direction of the slot length so as to provide free axial and angular movement of the bodies during their rotative movement. Apparatus is also provided for keeping the member centered in the slot, and includes a ball mounted on the center of each side of the member which rides in a semicircular longitudinal channel along the center of the slot sidewall and is freely slidable and rotatable therein.

Abstract: A vibration damper assembly providing for extended travel in the damper operation, wherein the assembly includes a hub having an integral radial flange and three circumferentially equally spaced radially extending hub arms, a pair of equalizers journalled on the hub on opposite sides of the flange, and a housing substantially enclosing the hub and equalizers and adapted to be secured to a torque input member. Each equalizer has three circumferentially equally spaced radially extending arms, with the arms of the two equalizers alternating between the hub arms. This assembly provides for three groups of damper springs acting in parallel with three spring sets acting in series in each group.

Abstract: The laying-in comb for a warp knitting machine has sinkers wherein the top edges are longitudinally offset relative to the bottom edges so as to impart rigidity to the sinkers. The amount of offset decreases from the securing end of the sinkers towards the head end of the sinkers. The sinkers may be permanently deformed by being cast into a mounting block or may be placed under tension by means of separate blocks which are movable relative to each other. The blocks may also be mounted on bars which are programmed in accordance with a suitable pattern.

Abstract: A warp-knit stringer tape for slide fasteners comprises a first set of yarns forming a knit ground structure containing stitch loops in every course and wale of the tape, and a second set of yarns knitted in the ground structure so as to form sinker loops located over the first set of yarns and each extending transversely across at least three wales, the second set of yarns including textured yarns. A third set of yarns are knitted in the ground structure so as to form chains of loops and extend along the wales in at least one of opposite tape edge portions. The first and third sets of yarns include multifilament synthetic yarns. A fourth set of yarns are laid in the ground structure and extend in and along the last-mentioned wales.

Abstract: A dyeing washing and/or milling machine particularly useful for dyeing woollen components including an annular working fluid reservoir and rotating paddle members which pass into and out of the reservoir to circulate the fluid therein. The apparatus may further include a heating system and a fluid pump and duct system, to heat and increase the circulation of fluid within the reservoir.

Abstract: A combination lock for suitcases, bags, or the like, is disclosed, in which a plurality of engageable blocking sleeves and corresponding number-setting dials cooperate with a latching slide member to permit the selective latching or unlatching of the device. The invention includes a separate portion of the latching slide member resiliently urged to the latched position, and which independently permits latching of the device even when the opening combination is not set on the number-setting dials. The device also facilitates resetting of the secret combination, and provides the further option of selectively blocking the latching function.

Abstract: A device for preventing a dead bolt handle from being turned, comprising a knob encompassing portion depending from a handle accommodating housing. Said encompassing portion and housing so coact that the tendency of said device to rotate on said handle being turned is barred by said knob encompassing portion abutting a door knob.

Abstract: An agricultural tractor with a hitching or lifting device which carries a farm implement. A control mechanism is provided on the tractor for adjusting automatically the height of the hitching device to enable the implement to follow irregularities in the underlying ground. The control mechanism includes a sensing member which, in one embodiment (FIG. 1), comprises two wheels which may pivot together about a common axis, such pivoting causing adjustment of the hitching device. In another embodiment, independently pivotable wheels or a further ground engaging member such as a skid may be located ahead of or behind the ground engaging wheels of a tractor which, by connection to the control mechanisms cause the hitching device to adjust to the height of the underlying ground.

Abstract: A method of rolling angle structural shapes in which a bar of rectangular ofile is rolled in a first step to form a blank having a rounded convex protuberance on one side and a flat opposite side. In at least one subsequent state, the blank is rolled to transform the protuberance or hump into a triangular protuberance or ridge with flanks lying substantially at a right angle, whereupon the blank is bent, after rounding the edges of the flat surface, to form the angle profile.

Abstract: A mill roll balance system for incorporation within a rolling mill is provided. The balance system includes a rigid beam assembly for guiding a portion of the mechanism utilized to stabilize the top roll and for preventing any resultant horizontal forces due to an unbalanced counterweight apparatus utilized to provide an upward force to the upper roll in the mill. A plurality of steelyard rods are provided and are continuous in their length from a point below the bottom of the roll housing through the housing to their upper terminus switches proximate the upper roll for providing the necessary counter-balancing upward force to the screw-down mechanism's downward force on the upper roll.

Abstract: Each jaw of a pair of jaws of an expandable jaw power tool are individually modified so as to accept a shaft supported in one jaw while passing through the other jaw of the same pair. The shaft includes an adjustable power distributing member which makes the depth of the jaws adjustable and makes greater use of the power stroke of the jaws, distributes the power or pressure output of the jaws over a wider area and makes an improved power tool, adjustable at the point of application of power stroke.

Abstract: In a gas measuring probe assembly having a gas sensing device located within a tubular housing positioned within a gas environment to be monitored, a tubular calibration gas flow pattern is established within the tubular housing substantially parallel to the walls of the tubular housing to sweep the monitored gas environment from the tubular housing and expose the gas sensing device to a calibration gas mixture substantially free of the monitored gas environment. This technique permits the in situ calibration of gas detectors, and is especially useful in calibrating stack gas monitoring probes.

Abstract: An electronic device for detecting and correcting pinking in an internal combustion engine by changing the ignition displacement of the internal combustion engine which comprises a vibration pick-up mounted on the internal combustion engine providing a signal to a band-pass filter for selecting a frequency band corresponding to pinking vibrations and a comparator, the output of which provides a signal for altering the ignition displacement of the engine and the two inputs which receive the output from the band-pass filter after it has undergone different treatments in two parallel channels, one channel comprising an integrator followed by an amplifier and the second channel preferably comprising an integrator, therebeing provided a gate between the band-pass filter and the two channels, which gate is only open for a predetermined angular zone during operation of the internal combustion engine.

Abstract: Cigarette testing system for cigarettes having perforations 6 in the filter in which the cigarette 2 is surrounded by a suction chamber 8 and the tobacco end is connected to a source of pressurized air. The pressure at the tobacco end is regulated in accordance with the average signal from a transducer 10 at the filter end so as to maintain zero average pressure at the filter end, i.e. so that the air flow into the cigarette from the tobacco end exactly balances the outflow through the perforations. The tobacco end pressure is monitored as a measure of the average dilution level of the cigarettes and the deviations from zero pressure at the filter end can be used as individual cigarette test signals.

Abstract: A fuel efficiency display device, in the form of an intake manifold suction measuring and display intended to be mounted within the passenger compartment of an internal combustion engine propelled vehicle, includes an elongated housing with a hollow open bottomed outer shell with a mounting boss extending lengthwise of it, a central, open ended sleeve with a cylindrical bore, the sleeve being spaced from and connected to an inside wall of the shell by spiders and a sight tube, fitting within the sleeve, through which an indicator spool slides. The sight tube has an annular shoulder which abuts the upper end of the sleeve.

Abstract: A method for measuring the air quantity supplied to an internal combustion engine by means of a measurement sensor disposed in a bridge circuit having a temperature-dependent resistor (for example, a hot wire or hot film) in the air intake manifold and having a temperature control apparatus, the temperature of the measurement sensor being controlled in an open or closed loop independently of the temperature of the medium to be measured, the properties of the medium to be measured which cause the measurement effect in the hot wire or hot film being dependent on the temperature. With an identical flow quantity but different temperatures in the medium, a correct measurement indication is obtained by making the excess temperature of the hot wire dependent on the temperature of the medium to be measured.

Abstract: A directional heat loss anemometer transducer for sensing both the speed and direction of motion of a fluid, liquid or gas in which the transducer is immersed. The transducer is constructed of fine long cylindrical resistive conductors which are axially disposed about a central, cylindrical supporting body, wherein at least two conductors serve as a direction sensing pair which can also be used to determine impinging fluid speed. The sensing conductor pair are joined together by an adhesive connecting means thereby preventing independent flow between the individual conductors of the conductor pair. The electrical conductors can be metallic or resistive films which are deposited on a cylindrical supporting body, or they may be individual wires of circular cross section. Each conductor is made of a material which exhibits a change in its electrical resistance as a function of temperature.

Abstract: An anti-clogging flume and structure for metering fluid flow over the flume wherein the flume is of a length sized to be inserted within a pipe and which flume has a generally cylindrical opening as an inlet at one end and a V-shaped outlet at the other end and the flume converges from the inlet end smoothly inwardly and upwardly to the outlet end with a spillway being defined at the outlet end, the spillway outlet being elevated with respect to the lowermost portion of the flume at the inlet end, and structure exterior of the flume for introducing gas into the flume adjacent the inlet end through a hole in the lowermost portion to bubble the gas through the flow along the flume adapting it for use with a recording device to meter, measure and record flow of water through the flume.

Abstract: A method of measuring the level of molten metal in a continuous casting m comprises inducing in the molten metal a magnetic field by a primary electrically energized coil and, by the relationship of this magnetic field to a pair of symmetrical secondary coils coaxial with the primary coil, inducing voltages in these secondary coils which are electrically connected in a circuit opposition so that the resultant voltage represents the level of the molten metal.

Abstract: Apparatus for determining the vapor content of a gas/vapor mixture comprises two temperature sensing devices. One of the devices measures the temperature of a liquid evaporating from a liquid saturated wick in contact with the device. The other temperature sensing device measures the temperature of the gas/vapor mixture in which it is immersed. A cooling device is provided for condensing some of the vapor from the gas/vapor mixture to maintain a liquid supply for the wick.

Abstract: In a continuous slab caster, for example, the system measures tundish molten steel temperature using tundish probe, recorder and temperature monitoring circuits having separate outputs to a temperature indicator and an industrial process controller. Monitoring circuits periodically reject errors and discontinuities in temperature traces, reject open thermocouple or burn-out conditions, and advise the probe operator by way of the indicator to accept a present good reading or take another sample. The last bonafide temperature reading is held at the output to the process controller, thereby eliminating control errors caused by errors or discontinuities in temperature traces.

Abstract: A liquid crystal temperature indicator that gives a visual indication of whether the device is at a temperature above or below one or more threshold values has a homeotropically aligned nematic or smectic layer incorporating a pleochroic dye. The color of the cell changes as the dye will only absorb normally incident light when the temperature causes the liquid to go isotropic. Electrodes may be provided to provide electronic detection of the passage of the liquid through the threshold temperature.