Abstract: A hood device for coupling cars comprises a first hood component having one end secured to one of a pair of car bodies to be coupled with each other and a second hood component having one end secured to the other car body and the other end adapted to be coupled with the other end of the first hood component, each of the hood components having side wall panels provided on both side portions thereof. Each side wall panels includes a fixed side wall panel having one end secured to the other end of the associated hood component, and a movable side wall panel having one end mounted on the associated car body and adapted to be turnable about a substantially vertical axis and the other end resiliently urged such as to be directed to the inner surface of the adjacent fixed side wall panel.

Abstract: A housing adapted to be mounted beneath the top of a table and a shelf sized to fit substantially within the housing are operatively connected by a pair of telescoping rails which guide movement of the shelf between a retracted position in which the shelf is substantially within the housing and an extended position in which the shelf has a substantial portion thereof outside the housing. The rails pivot about an axis to change the height of the shelf with respect to the top of the table and the entire assembly includes a mechanism for securing the shelf in the extended position. The housing includes a vertically stepped slot in which a pin secured to the rails is movable to hold the shelf at predetermined heights with respect to the top of the table corresponding to the steps of the vertically stepped slot.

Abstract: A lifting table top mechanism is provided wherein a table top can be raised or lowered between two stable positions with respect to the table base, by means of moving a handle. The handle is incorporated into a rotating bar which is configured so that, when attached to the lower faces of a lower plate attached to the table base and one or two upper plates attached to the table top, movement of the handle causes the upper plates to be drawn toward or pushed away from the lower plate. A connecting bar, configured to be attached to the lower plate and upper plates, rotates in tandem with the rotating bar. A linear linking member links each end of the rotating bar to the corresponding end of the connecting bar. The upper plates are stablized in one of two positions: adjacent to the lower plate or at a maximum distance permitted by the configuration of the connecting bar and rotating bar.

Abstract: A housing contains a plurality of vertically spaced shelves movable vertically relative to each other upon activation of a fluid pressure piston-cylinder unit mounted on the housing. Elongated suspension rods depend from the top shelf to support the next two adjacent shelves for relative vertical movement, and each subsequent lower shelf is similarly supported by a shelf above it but separated from it by one intervening shelf. The two top-most shelves also are arranged to be secured together detachably in abutting relationship. The lower end of each suspension rod mounts a rotary disc which supports a pair of upstanding spaced pins arranged in one position of rotary adjustment to abut the underside of a lug extending laterally from the adjacent shelf, and in a second position of rotary adjustment, 90.degree. from the first position, to register with openings in the lug, whereby the associated shelf is lowered from the first position of support a distance substantially equal to the length of the support pins.

Abstract: A method for drying, crushing and distribution of solid fuel for a solid fuel boiler, for example a fluidized bed boiler. The method is characterized in that moist fuel is crushed and dried by intermixing gas and/or ash, and that the fuel is set in motion, for example in a cyclone together with gas, the fuel thus being divided into several sub-flows for feeding into the boiler at different points.

Abstract: Disclosed is a burner for the partial combustion of a carbonaceous fuel, wherein e.g. coal and oxygen are supplied to a reactor space and heat from the combustion is transferred from the burner face by means of a heat pipe to a fluid cooled section of the burner.

Abstract: A simple, one person transplanter in use from a standing position having a rectangular, tubular frame, the distance equivalent to the distance required between plants, and a dibble on one end to make the hole for the container which also spaces the plants the proper distance and having a hollow delivery chute for the containerized plants and a pair of opposed trowels for closing the soil around the container and also a platform secured to the upper end to support flats whereby the person doing the transplating is in a standing position at all times.

Abstract: In an automatic sewing device for sewing together tubular workpieces such as sleeves, and pocket-shaped workpieces, such as cuffs, there are provided an inner clamp, a central clamp and an outer clamp. These clamps are associated with an inner sleeve clamp and an outer sleeve clamp, the latter being associated with a folding device for gathering up a material fullness of the tubular workpiece. Devices are also provided for opening the pocket-shaped workpiece in order that the border of the tubular workpiece may be inserted and positioned. The associated sewing machine can be moved in a straight line relative to the parts described. A part of the border of the tubular workpiece is positioned in the pocket-shaped workpiece and sewn to the latter by means of a straight-line seam. Subsequently, the clamping in this area is released and the positioning of the border of the tubular workpiece in the pocket-shaped workpiece is carried out and clamping is effected.

Abstract: A looper drive for a chain stitch sewing machine, in which the joint between a connecting rod driven by a main shaft and a lever seated on a swivel shaft is a sliding and swiveling joint. Upon rotation of a ball eccentric, the transverse component of the rotary motion of a spherical shell is enabled by a rod sliding in bearing eyes on a bifurcated lever and the swinging motion of the lever, caused by the longitudinal component of the rotary motion of the spherical shell is enabled by the rod turning in the bearing eyes.

Abstract: A devised shank is provided to a presser foot of a sewing machine in addition to an ordinary shank, such that a special presser group for straight stitching along a fabric edge is attached to the devised shank only, in which the presser foot is attachable to a presser holder, and the ordinary shank is for such as zigzag stitching, and the devised shank is different in an attaching width from the ordinary shank. Signal generating parts are provided to the presser holder, which each issue a signal in response to when the presser foot is attached, and the signal is discriminated with a signal issued in response to a pattern group belonging to patterns selected by a pattern selecting means so that the sewing machine is driven only when the presser group and the pattern group is met.

Abstract: A thread take-up device comprising a loop tightening member adapted to reciprocate within a predetermined range limited by a thread slackening limit position where the loop tightening member is located when a thread loop is expanded to its maximum extent by a loop-seizing member, and a loop tightening limit position for tightening the thread loop; and a movable member adapted to reciprocate within a predetermined range limited by a stopping position defined within the range of reciprocation of the loop tightening member above the loop tightening limit position, and a position corresponding to the thread slackening limit position of the loop tightening member. The respective loci of the recess for engaging the needle thread of the loop tightening member, and the thread catch of the movable member overlap each other.

Abstract: A method of sewing the corners of a double seam, employing a two-needle machine the two needle rods of which each may be mutually independently engaged and disengaged. The method uses control means to arrive at the corner point of the inner seam, disengaging the internal needle rod, furthersewing to the corner point of the outer seam, stopping the sewing machine with the outer needle penetrating the workpiece, then rotating the workpiece, sewing the thus rotated outer seam, and engaging the inner needle rod.

Abstract: This disclosure relates to a small craft comprising a hull, a control handle supported on the hull adjacent its bow for pivotal movement in a substantially vertical plane that includes the center line of the hull. The handle extends rearwardly over the hull and is adapted to be manually operated. A wing is connected to the handle so as to have an angle of attack which changes as the handle is pivoted.

Abstract: A vibration damping arrangement for a structural member including leaf springs extending horizontally from a vibration absorber body adapted to be attached to the structural member. A set of horizontal-vibration-absorbing leaf springs extends in one horizontal plane while a set of vertical-vibration-absorbing leaf springs extends in another horizontal plane. A weight is mounted on the distal end of each leaf spring. The relative positions of the leaf springs in their respective planes are staggered around a vertical axis.

Abstract: A combination trailer and pontoon boat is disclosed in which the supporting wheels are attached to the boat by a confining track. This provides for the controlled launching and landing of the boat while the supporting wheels are fixed in place on dry land. Ramps permit the loading of the towing vehicle onto the boat while both are on dry land. A towing structure moves beneath the boat during loading and off-loading of the tow vehicle and is then pivoted upward in the waterborne mode. The supporting wheels are winched from their position beneath the boat rearward and upward along the confining track in the waterborne mode. The combination trailer and pontoon boat is a towable, one vehicle ferry.

Abstract: A device for applying adhesive material to card blanks in a packeting machine, comprising a gumming roller and a pressing roller which are substantially mutually tangential and between which the blanks are led in succession to receive traces of adhesive material in predetermined zones. Should the packeting machine halt for a time exceeding a predetermined time limit, detachment means withdraw from the gumming roller that blank disposed between the two rollers in order to prevent it becoming stuck to the gumming roller.

Abstract: In accordance with one embodiment of the invention, solder masking material is pressurized by means of a fluid pump to approximately 250 psi and high speed valve is used to turn the flow on and off rapidly in order that small "shots" of fluid are propelled from a tip, through the air, to selected portions of a circuit board. The selected areas of the circuit board to be masked are situated oppositely from the tip , as by a XY positioning system for the tip and/or the circuit board. The drops of masking material, which form upon impinging of the shots onto the circuit board, may be varied in volume and diameter. Where needed, a continuous bead of masking material may be formed on the circuit board by spacing the dots sufficiently close together.

Abstract: A metal organic chemical vapor deposition reactor 10 which includes a flat plate flow channel gas delivery system 18. The gas delivery system comprises slotted rods 40, 42 which pass through an assembly 46 of seal plates 52 and gas directing plates 50. Gas directing plates 52 provide separate flow channels for reactant gases in rods 40 and 42. Reactants are directly jetted from the gas directing plates onto a substrate 20 prior to mixing.

Abstract: Animal litter made from or in conjunction with a porous, odor-preventing material with a clearly defined pH-value, characterized in that the pH-value of the porous inorganic material in aqueous suspension is betwen approximately 7 and 9, preferably 7.5 and 8.5, that the porous inorganic material has a zinc content of 0.1 to 2.0% by weight and that the water-soluble zinc proportion of the porous inorganic material is 0.01 to 100 ppm, as well as a process for the production thereof.

Abstract: A cardboard insert for use in the bottom of a box for containing liquid deposited on the floor of the box has upturned edge flaps with connecting dam portions that are raised above the level of the insert when the edge flaps are erected, to provide a limited liquid retention capability to the box. In the case of the preferred embodiment, for a pet transportation box, the box is made of single ply corrugated board, as is the insert; and one face of the insert is made liquid proof preferably by way of a wax impregnation layer.

Abstract: A portable habitat and harvesting apparatus for marine life such as stone crab, crayfish, lobster and the like deployable on the water bottom and comprising a length of flexible cord connectable at each end to a separate end weight. A plurality of hollow containers are also included, each having an opening and connectable to and along the length of the cord. The invention is deployable on the water bottom in large quantities from a small boat, facilitated by the simplicity and compactness of its components which are easily assemblable during deployment. The invention may also include one or more midweights each positioned between adjacent containers along the cord to assist in maintaining the containers against the water bottom and in an orientation wherein the container interior is generally horizontally disposed in relation to its opening.

Abstract: A device for the long-term securing or "housing" of large or aggressive monkeys on poles within an enclosure is disclosed wherein a tether with rotatable joints is connected at one end to a collar around a monkey's neck and at the other end to a ring loosely fitted around a vertical climbing pole attached to horizontal support means, with perch means, and with a source of food and water being applied to each monkey, and with removable side walls, and with doors, permitting access to each individual monkey, and with all escape routes from the device closed by a ceiling and a floor, wherein each monkey may climp up and down its climbing pole freely with the ring sliding up and down the pole, and wherein the monkeys may make close physical contact with the other monkey similarly restrained within the device without their tethers becoming entangled, and wherein a plurality of such devices may be placed with their side walls alongside each other and connected by conventional means and their side walls removed, whe

Abstract: A device for picking up animals such as chickens from a ground surface and for conducting them away, comprising a frame, a suction conveyor arranged on the frame and provided with suction means and delivery means adjoining said suction conveyor. The suction conveyor comprises a suction surface having suction apertures through which the suction means can suck in air and guiding and driving means for moving animals picked up by the suction surface towards the delivery means.

Abstract: A fluidized bed heat generator with improved collector for ash removal and heat recovery comprises a central hearth having a fluidization grid at its lower end. The side wall of the hearth is enclosed by a hollow peripheral enclosure to define an intermediate volume therebetween which is connected both to the upper part of the hearth and to fume tubes. These fume tubes extend through the peripheral enclosure and open into a fume exit conduit such that fumes and entrained ash from the hearth can be directed via the intermediate volume and the fume tubes to the fume exit conduit. Water is arranged to circulate within the peripheral enclosure around the hearth and fume tubes.

Abstract: A self purging dual fuel injector has a valve which is pressed down, as opposed to lifting, to provide a pilot charge to the combustion chamber. As the valve further extends from the injector the pilot fuel flow is cut off and coal water slurry flows through the valve to the combustion chamber. During shut off of the slurry the retracting valve allows a shot of pilot fuel to purge the valve passageways.

Abstract: In a steam generator, there is provided an annular foraminous or perforated flow distribution plate (100) which may be in the form of a single-piece annulus fixedly secured to the lower end of the heat exchange tube wrapper (146) for installation within new steam generator facilities, or alternatively, may comprise a plurality of arcuately-shaped segments (210) secured together by suitable bolt fasteners (226) for installation within existing steam generator facilities. The plate (100) is adapted to be wedgingly interposed between the lower end of the tube wrapper (146) and the upper surface (204) of the heat exchange tube bundle tubesheet (122), and the plate (100) has the configuration of a conical frustum for stability.

Abstract: This invention relates to an internal combustion engine including a plurality of groups of combustion chambers and at least a first expansion chamber and a second expansion chamber. The first and second expansion chambers extend in a lengthwise direction and are separated from each other by a partition wall. The first expansion chamber is connected with one group of combustion chambers through separate branch passages. The second expansion chamber is also connected with another group of combustion chambers respectively through separate branch passages. First and second intake passages are connected at downstream ends with the first expansion chamber and the second expansion chamber, respectively. An auxiliary communicating passage is provided along the partition wall independent from said first and second intake passages and connects the first and second expansion chambers with each other.

Abstract: An engine comprises an output shaft journalled in a crankcase for rotation about an axis, an even number of cylinders, each having its axis parallel to the shaft axis, arranged in diametrically opposite pairs radially equidistant from the shaft axis and equally spaced-apart circumferentially, and a piston movable axially along each cylinder. A cross-head beam for each pair of pistons is connected to the respective pistons and journalled on a carrier that is received on the shaft for rotation with and movement axially along the shaft. A mechanism selectively moves the carrier axially along the shaft to vary the clearance volumes of the cylinders. The engine operates on a six-stroke cycle consisting of a four-stroke combustion cycle followed by a two-stroke steam cycle. The water injected for the steam cycle cools the engine. The intake air for the combustion cycle is supercharged and preheated before induction.

Abstract: A cooling system for a two-stroke engine including a water jacketed cylinder having cooling passages located beneath the exhaust port and beneath the transfer ports in the cylinder wall. Liquid coolant flows upwardly from the crankcase structure into the cylinder wall cooling jacket and finally upwardly into the head.

Abstract: A valve gear for a four-cycle engine having an overhung crankshaft connecting with an output shaft, wherein a guide portion having such a shape folding the output shaft as to return back to a starting point in two turns, is formed on the output shaft, and an interlocking mechanism guided by the guide portion is provided to open the valves for the four-cycle engine. It is preferable that the guide portion is formed as cam face displacing the interlocking mechanism. The guide portion can be formed on a block other than the output shaft for easy machining and also for adjustable valve timing.

Abstract: A combustion control system for internal combustion engines which includes a novel spark plug having a precombustion chamber in which a butane/air mixture injected through the plug is ignited in order to initiate and manage combustion wave propagation within the engine cylinder. The system also includes a fuel system to provide gasoline at an elevated pressure to the fuel metering system of the engine and a gaseous air/butane mixture under pressure to the spark plugs.

Abstract: A system for limiting the maximum speed of an internal combustion engine comprising an electronic injection system, which system comprises first means for detecting when the speed of the engine exceeds a first given threshold value, and for consequently disabling fuel supply to the injectors, and second means for determining whether the speed of the engine exceeds a second given threshold value higher than the first threshold value, and for consequently maintaining disabled or enabling fuel supply.

Abstract: An idling speed control system for controlling idling rotational speed of an internal combustion engine. A vacuum-operated actuator having a diaphragm defining a vacuum chamber controls opening and closing of a throttle valve in response to first and second control pressures supplied from a change-over control valve to the vacuum chamber. An electronic control unit generates, in response to an on-off control pulse signal having a period corresponding to rotational speed of the engine, one of on-period and off-period of the on-off control pulse signal having a predetermined constant value, and supplies the change-over control valve with the control pulse signal. Preferably, a detector is connected to the electronic control unit for detecting a change in the magnitude of a load on the engine and supplying the electronic control unit with an output signal indicative of the detected change in the load magnitude.

Abstract: A boost compensator for controlling the position of a control rack of a fuel injection pump to supply fuel to an internal combustion engine with a supercharger in response to boost pressure to be applied to the engine. The control rack is moved in a direction increasing an amount of fuel to be supplied to the engine, by angular movement of a main lever in one direction during forward movement of a push rod in response to an increase in the boost pressure from a first to a second set value. As the boost pressure reaches a third set value higher than the second set value, the push rod is brought into engagement with an auxiliary lever biased by a return spring.

Abstract: A system for automatically defining the minimum setting of a valve controlled by an accelerator for supplying air to an internal combustion engine, which system comprises means for repeatedly detecting the setting of the valve in relation to a given minimum setting value; which means define a new given minimum setting value, should the setting of the valve remain steadily, in excess of given time limits, within setting limits respectively over and below the aforementioned given minimum setting value.

Abstract: A system and method for deciding the ignition timing at the acceleration of an engine and the steady state. The system has an acceleration ignition timing correction subroutine and a steady state ignition timing correction subroutine. In the acceleration ignition timing subroutine, a basic ignition timing obtained in the steady state ignition timing correction subroutine is corrected by a quantity read from a table so as to sufficiently advance the ignition timing for the acceleration and the steady state.

Abstract: Controlling operation of an internal combustion engine at lean air fuel ratios uses an in-cylinder pressure sensor. The in-cylinder pressure sensor is coupled to each cylinder of the engine and measures in-cylinder pressure and generates an output signal as a function of such pressure. Airflow into the engine is also sensed and both the airflow and in-cylinder pressure are applied to the fuel controller for generating a fuel injection drive signal. Compensation means coupled to the in-cylinder pressure sensor means and airflow indication means modify the fuel air command applied to the engine as a function of airflow and in-cylinder pressure. The compensation means is also coupled to the fuel controller for applying a fuel command signal to the fuel controller thereby permitting engine operation at the lean air fuel ratio limit.

Abstract: A fuel injection system for an internal combustion engine comprises a fuel injecting valve, L-jetronic calculating means for calculating the amount of fuel to be injected based upon the output from an air flow meter under an engine operating condition where the amount of intake air is small, D-jetronic calculating means for calculating the amount of fuel to be injected based upon outputs from engine load detecting means and engine rpm detecting means under an engine operating condition where the amount of intake air is large and correcting means for correcting the amount of fuel to be injected upon switchover between the L-jetronic and D-jetronic calculating means in response to engine operating condition changes. As a result, the difference between successive amounts of fuel to be injected is never large. of fuel injected lastly.

Abstract: In determining an optimum target fuel ignition timing in accordance with the engine operating conditions, including at least an engine load and an engine speed, the target ignition timing is determined on the basis of a corrected engine load and a corrected engine speed. The corrected engine load and corrected engine speed are obtained by making corrections, according to the engine operating conditions, to a detected engine load and a detected engine speed, respectively. In this way, the optimum target fuel ignition timing according to the engine operating conditions can be obtained without directly detecting a fuel injection quantity.

Abstract: A highway truck having a mobile frame and an engine compartment having a forward facing air inlet at the front of the frame disposed to receive ram air from the travel of the truck, a radiator mounted on the frame adjacent the air inlet, and a charge air cooler mounted adjacently above the radiator and adjacent the engine compartment air inlet for parallel ambient air flow therethrough. The air manifolds or plenums of the cross flow charge air cooler preferably have vertically centered rearwardly facing openings to eliminate bends in the ducts connecting to the engine while providing an optimum manifold design.

Abstract: An exhaust gas recirculating system provided with exhaust gas recirculation interrupting means which operates to make the exhaust gas recirculation control valve interrupt recirculation of the exhaust gas when a traction control system for preventing wheel slip is operated.

Abstract: A gas downdraft range is provided with an airflow system for inducing and maintaining cooling airflow, combustion airflow and exhaust airflow. A housing defines an upwardly facing burner box and a cover overlies the housing with a downwardly formed burner pan disposed within the burner box. The bottom wall of the burner pan is spaced above the bottom wall of the burner box to form an air space therebetween. The burner box has cooling air inlets and cooling air outlets in communication with the air space to define a cooling airflow path. A burner is operably disposed in the burner pan and a grill grate overlies the burner pan providing combustion air inlet and outlet ports to and from the burner pan for defining a combustion airflow path. A plenum enclosure is connected to an exhaust air intake juxtaposed the grill grate and exhausts to atmosphere defining an exhaust airflow path. A blower concurrently induces and maintains each of the airflows.

Abstract: A heating system comprising a firebox defining a combustion chamber that is substantially sealed from the atmosphere. The system includes a flue for conducting combustion gases from the combustion chamber. A first duct surrounds the flue and defines an inner passageway with respect thereto. A second duct surrounds the first duct and defines an outer passageway. An inlet means is provided for introducing ambient air into the outer passageway. The air in the outer passageway is drawn through the inner passageway by a negative pressure in the combustion chamber. The ambient air in the inner and outer passageways is heated by heat transmitted from the flue. This heated ambient air is then introduced in the combustion chamber to improve the efficiency of combustion.

Abstract: A novel anti-G suit valve system is disclosed which provides very rapid response to imminent high acceleration. The disclosed embodiments of the new valve system can be retrofitted to existing mechanical anti-G valves to create a hybrid valve system capable of achieving the desired qualities of fast triggering of the valve in response to imminent acceleration and maximum rate inflation of the anti-G suit. The new valve system measures acceleration and, by differentiation, the rate of change of acceleration. When both acceleration and rate of change of acceleration exceed preselected values, a solenoid mounted in place of the press-to-test button on a mechanical anti-G valve is energized for a preselected period of time to fully depress the valve spindle, providing maximum rate delivery of pressurized air. The hybrid valve reverts to normal operation at the end of the preselected period of time.

Abstract: Disclosed is a construction of an endoscopic fluid changing device which, attached to an endoscope, regulates the flow of a fluid in a channel of the endoscope.

Abstract: A sterilizable catheter of micro-thin diameter has a central coherent fiber bundle for carrying an image to a viewing means, which is surrounded by light fibers. The proximate end of the catheter is provided with a coupling means for aligning the coherent optical bundle with the optical system of the viewing means and for providing an interface with light transmitting means to transmit light from a light source to the body cavity. The coupling means has a diameter no bigger than the diameter of the covering of the catheter. When the catheter is used in a trochar, the trochar can be removed while the catheter remains in place. This is accomplished by removing the viewing means and sliding the trochar over the catheter and then replacing the viewing means for further viewing within the body cavity.

Abstract: An endoscope having a light source unit, a light guide fiber for guiding illumination light from the light source unit to the distal end in the inserting section of the endoscope main body, an optical system provided in the distal end for guiding the illumination light transmitted via the light guide fiber to an object, and a solid-state image pickup element incorporated in the distal end. A lens of the optical system is supported by a frame movable along an optical axis thereof. The frame is moved along the optical axis by a wire operating device provided in a control section of the endoscope main body in order to vary the angle of view of the optical system, i.e., the illuminating angle of the illuminating light. The image obtained by the solid-state image pickup element is enlarged by an image enlargement processor in accordance with the angle of view of the optical system, and is displayed. The image enlargement processor has a first frame memory and a second frame memory.

Abstract: A back massager device which comprises a back support, a footrest connected adjacent to one end of the back support and a headrest connected to the opposite end of the back support. The back support is positioned on resilient padding placed on a support table. The back support is preferably in the form of a pair of spaced longitudinally extending bars inserted in a cushioning material. A first series of vibrators is connected to one of the support bars and a second series of vibrators is connected to the other support bar. In the preferred embodiment, the vibrators each comprise an electrical coil, a magnet associated with the coil for actuation thereby, the magnet being mounted on a vibratable arm, and a member connecting the arm and a support bar for vibration thereof in response to actuation of the magnet by the coil. Structure in the form of an adjustable screw is provided on the vibratable arm for varying the amount of vibration transmitted to the support bar.

Abstract: An improved cervical traction apparatus comprises a cradle including a bowl-shaped cranial cavity for supporting the head of a user and an occipital shelf support comprising a concave wall extending across the cradle. The cradle is secured on a base assembly which provides for movement of the cradle relative thereto to provide for both independent horizontal and vertical plane movements.

Abstract: An improved tibial cutting jig is provided for use in obtaining accurate tibial resection in the course of a total knee prosthesis implantation procedure. The tibial cutting jig includes a base for sliding reception onto an intramedullary alignment rod preinstalled generally along the longitudinal axis of the tibia. The base includes laterally extending outriggers carrying removable measurement keys of selected size for spacing the base above the tibial plateau by a selected dimension. An anterior saw guide depends from the base and is thus positioned relative to the tibial plateau in accordance with the sizes of the measurement keys.