Abstract: Rotor for a rotor-type locking device operated by a key, said rotor presenting: a central chamber; a series of slots; locking tumblers with nib, in which at least one tumbler is brought into the unlocked position by a displacement in a direction different from the unlocking direction of at least two other tumblers, the nibs of said tumblers extending along a same face of the chamber.

Abstract: Thiol ester compositions, methods of making the thiol ester compositions, and methods of using the thiol ester compositions are provided. In some embodiments, the thiol ester compositions include thiol esters, hydroxy thiol esters and cross-linked thiol esters. The thiol ester composition can be used to produce cross-linked thiol esters, sulfonic acid-containing esters, sulfonate containing esters and thioacrylate containing esters. The thiol ester compositions can be used to produce polythiourethanes. The polythiourethanes can be used in fertilizers and fertilizer coatings.

Abstract: The present invention relates to a method for forming three-dimensional mark on a cylindrical tool and a die for forming the same, wherein the method includes the steps as: first, material preparation: choosing a cylindrical tool as a raw material; second, forming an identification area: forming the identification area on a surface of the raw material; third, roll-and-press forming: forming a projecting three-dimensional identification unit by pressing and rolling the identification area of the raw material with a die. The die is formed at a terminal surface with an abutting portion, and at both sides of the abutting portion is formed two guiding portions, the abutting portion is formed with an identification groove, the guiding portions are inclined relative to the terminal surface of the die.

Abstract: A method and apparatus are provided for rolling outer fillets of arcuately offset, split pin bearings on crankshafts with a pair of work rollers, each pair engaging and rolling a respective outer pin fillet. A backup roller is positioned opposite the pair of work rollers. The work rollers may be positioned above and below a centerline of the split pin, preferably about 90° apart. The work rollers can perform identical rolling operations at identical pressure and the work rollers and backup rollers are positioned to keep the adjacent tool heads in parallel planes during these rolling operations. Rolling arms carry the tool heads and stops are provided to keep rear portions of the tool arms in parallel planes against sideways forces. The work rollers and the backup roller may be mounted on the same tool arm and are movable relative to each to clamp or release a pin bearing.

Abstract: A hemming method for performing a 180 degree hem between an inner panel and outer metal panel. A curvilinear prehemming tool is then moved in a direction substantially parallel to the plane of the inner and outer panels so that the prehemming tool contacts a protruding coupon on the outer panel and creates a bend line in the coupon at a position spaced outwardly from the outer edge of the inner panel. Thereafter, a final hemming tool moves relative to the panels in a direction substantially parallel to the original plane of the inner and outer panels. This final hemming tool includes a first curvilinear surface which initially contacts the coupon and rolls the coupon such that the edge of the coupon contacts the inner panel. Thereafter, a generally planar wedge section of the final hemming tool contacts the coupon and compresses the coupon against the inner panel thus completing the hemming operation.

Abstract: A test system for assessing the performance of an analyzer for a gas or an anesthetic agent includes a source of a calibration gas mixture, a valve for controlling flow of gas from the source, a low-pressure tube, a sample tube in communication with the low-pressure tube, and a connector for assembling the analyzer to the test system. The test system may also include a valve for diverting ambient air into the sample tube instead of the calibration gas mixture. Additionally, the test system may include one or more of a barometer, a flow meter, an analyzer for gas or anesthetic agents, a flow restriction system, and a relatively high pressure source. Methods for testing analyzers are also disclosed.

Abstract: Particular aspects of the present invention provide novel systems and methods for method for epidemiological and environmental monitoring and assessment, and for active management of human health hazards associated with building environments. In particular aspects, the inventive system and methods are used as a human health and environmental health management tool for corporations (e.g., offices, factories), commercial buildings, condominiums, hotels, resorts, camps, military installations, schools, daycares, cruise ships, real estate developments, towns and cities, prisons, or any other institutional or community settings. In particular aspects, the inventive system and methods are used in a proactive manner to maintain the health of building occupants. Additional aspects provide systems and methods having substantial utility as an investigative tool to substantiate human health claims and correlate underlying environmental factors.

Abstract: The sensing apparatus for a vehicle includes a case having an opening part formed so as to communicate with an outside. A printed circuit board is disposed inside of the case, and includes a circuit unit. A noxious gas sensing part is electrically connected with the circuit unit for sensing a noxious gas of an external air inflowing through the opening portion, and for outputting a sensing signal. A connector is disposed at least partially with the case, one end thereof being directly connected with the circuit unit, and the other end thereof being directly connected with an external device.

Abstract: A selective gas sensor comprises a semiconducting substrate, a radiation source that directs narrowband radiation to the semiconducting substrate; and a plurality of electrodes coupled to the semiconducting substrate, whereby a gas is selectively sensed. A method of selectively sensing a gas comprises the steps of contacting the semiconducting substrate with a gas, directing narrowband radiation to the semiconducting substrate and sensing the resistance of the semiconducting substrate, thereby selectively sensing the gas.

Abstract: An apparatus and method to sense the onset of combustion stability is presented. An electrode is positioned in a turbine combustion chamber such that the electrode is exposed to gases in the combustion chamber. The electrode may be integrated with an igniter. A control module applies a voltage potential to the electrode and detects a combustion ionization signal and determines if there is an oscillation in the combustion ionization signal indicative of the occurrence of combustion stability or the onset of combustion instability. The control module broadcasts a notice if the parameters indicate the combustion process is at the onset of combustion instability or broadcasts an alarm signal if the parameters indicate the combustion process is instable. Combustion parameters are adjusted to drive the combustion process towards stability.

Abstract: In a method for testing the integrity of welds at elevated temperatures, a pressurized mixture of a gaseous environmentally safe composition is injected in an area between the inner and outer weld of a terminal flange welded to a tubular pipe section or casing. The pressurized composition includes a marker sub-composition which is detected by a detection apparatus which scans the weld. The pressure of the gas composition is also monitored to observe losses in pressure indicative of flaws in the welds. The integrity of the welds is tested at elevated temperature permitting remedial repairs to be made without reheating the tubular pipe or casing.

Abstract: A rotational rheometer or viscometer has a measuring motor for driving a measuring shaft which carries a measuring system, Particularly a measuring head supported by a shaft portion, which may be contacted with a substance to be examined. Measuring data are introduced into the calculation of the properties, particularly the viscosity, of the substance. The measuring system has a characteristic identification with data referring to its properties, such as the geometry, the type, and/or the construction of the measuring head. An encoder module enables contactless reading the information. The data transmission path between the measuring system and the uptake or receiver unit has at least one section where the data may be transmitted wirelessly or over an air transmission path or air main path.

Abstract: A cantilever probe-based instrument is controlled to counteract the lateral loads imposed on the probe as a result of probe sample interaction. The probe preferably includes an active cantilever, such as a so-called bimorph cantilever. Force counteraction is preferably achieved by monitoring a lateral force-dependent property of probe operation such as cantilever free end deflection angle and applying a voltage to at least one of the cantilever and one or more separate actuators under feedback to maintain that property constant as the probe-sample spacing decreases. The probe could further uses at least one of contact flexural and torsional resonances characteristics to determine contact and release points. With the knowledge of the tip profile, quantitative mechanical data for probe sample interaction can be obtained.

Abstract: A method and system for determining a combustion misfire in an internal combustion engine by calculating a segment time; normalizing the calculated segment time; modifying the normalized segment time using low pass filters for each cylinder; calculating a misfire determination reference value by adding a minimum value among the modified normalized segment times to a predetermined offset value; and determining whether a combustion misfire occurs based on a comparison of the modified normalized segment time and the misfire determination reference value.

Abstract: Sensor systems and methods are disclosed, which generally incorporate isolation between the sensor's electronics and the sensed media. The sensor's electronic circuit can incorporate one or more application specific integrated circuit (ASIC) that processes and outputs the signal for both absolute and differential measurements. Such a sensor can be adapted for use in exhaust gas re-circulation (EGR) systems utilized with automotive gasoline engines. Such a sensor can also be utilized for measuring differential pressure across diesel particular filters and/or applications in which differential pressure is required for system control and/or monitoring purposes. The absolute pressure sensor disclosed herein can therefore sense the exhaust pressure on automotive engines and other mechanical and/or electromechanical devices and machines.

Abstract: A tire maintenance gauge including a first sensor engageable with a tire to measure a first tire parameter. A first indicator is movable in response to the measured first tire parameter. A second sensor is engageable with the tire to measure a second tire parameter. A second indicator is movable in response to the measured second tire parameter.

Abstract: Exfiltrometer apparatus includes a container for holding soil. A sample container for holding sample soil is positionable with respect to the container so that the sample soil contained in the sample container is in communication with soil contained in the container. A first tensiometer operatively associated with the sample container senses a surface water potential at about a surface of the sample soil contained in the sample container. A second tensiometer operatively associated with the sample container senses a first subsurface water potential below the surface of the sample soil. A water content sensor operatively associated with the sample container senses a water content in the sample soil. A water supply supplies water to the sample soil. A data logger operatively connected to the first and second tensiometers, and to the water content sensor receives and processes data provided by the first and second tensiometers and by the water content sensor.

Abstract: A forced harmonic vibration master gear for use in a device for detecting imperfections in a production gear includes a gear body having a plurality of gear teeth. Each of the plurality of gear teeth has a graduation of material added thereto extending from a form diameter of each tooth to an end of the tooth to decrease the pressure angle of the tooth. The forced harmonic master gear when used to test an unacceptable production gear, induces in the unacceptable production gear, when rotating, a vibrational force that is at least 50 percent greater than a vibrational force exhibited by the unacceptable production gear when a standard master gear is used to test the unacceptable production gear, in at least one band of 70 Hz to 150 Hz, 151 Hz to 300 Hz, 301 Hz to 550 Hz, 551 Hz to 1250 Hz and 1251 Hz to 2000 Hz.

Abstract: A method for determining rotor blade deflection, wherein a rotor blade is coupled to a hub, includes coupling a first end of a beam to the rotor blade, positioning a second end of the beam adjacent the hub, measuring the deflection of the beam using at least one sensor, and determining the deflection of the blade based on the deflection of the beam.

Abstract: A thermal flow sensor has a first substrate, second substrate and a third substrate, each of which has a first side and a second opposite side. The first substrate is connected to the second substrate such that the second side of the first substrate abuts the first side of the second substrate. The third substrate is connected to the second substrate such that the second side of the second substrate abuts the first side of the third substrate. The second substrate has a groove formed therein so as to form a conduit bounded by the second substrate and the second side of the first substrate and the first side of the third substrate. A heater is disposed on the first side of the first substrate opposed to the conduit. A first temperature sensor is disposed on the first side of the first substrate opposed to the conduit.

Abstract: A thermal flow sensor has a first, second and third substrate, each having a first side and a second opposite side. The first substrate is connected to the second substrate such that the second side of the first substrate abuts the first side of the second substrate. The third substrate is connected to the second substrate such that the second side of the second substrate abuts the first side of the third substrate. The first, second and third substrate form a multi-layer body structure having at least one edge extending between a first side of the first substrate and the second side of the third substrate. The second substrate has a groove formed therein so as to form a conduit bounded by the second substrate and the second side of the first substrate and the first side of the third substrate. The conduit has an inlet opening and an outlet opening that are formed in the at least one edge.

Abstract: A thermal flow sensor has a first, second and third substrate, each having a first side and a second opposite side. The first substrate is connected to the second substrate such that the second side of the first substrate abuts the first side of the second substrate. The third substrate is connected to the second substrate such that the second side of the second substrate abuts the first side of the third substrate. The second substrate has a groove formed therein so as to form a conduit bounded by the second substrate and the second side of the first substrate and the first side of the third substrate. The conduit has a fluid flow direction. A heater is disposed on the first side of the first substrate opposed to the conduit. A first temperature sensor is disposed on the first side of the first substrate opposed to the conduit and at a first predetermined distance from the heater in a direction opposite to the fluid flow direction.

Abstract: A thermal flow sensor has a first, second and third substrate, each having a first side and a second opposite side. The first substrate is connected to the second substrate such that the second side of the first substrate abuts the first side of the second substrate. The third substrate is connected to the second substrate such that the second side of the second substrate abuts the first side of the third substrate. The second substrate has a groove formed therein so as to form a conduit bounded by the second substrate and the second side of the first substrate and the first side of the third substrate. A heater is disposed on the first side of the first substrate opposed to the conduit. A first temperature sensor is disposed on the first side of the first substrate opposed to the conduit. A second temperature sensor is disposed on the first side of the first substrate opposed to the conduit.

Abstract: The present invention relates to a radar level measuring device for non-contact measurement of a level of a product in a container. The device comprises a flange which is mounted on the container in such a way that a lead-through of the flange at least partly covers an opening in the container. The device further comprises a waveguide part, insertable into the flange. When inserted, the insertable waveguide part is arranged to come to a stop at a distance (D) from the surface of the flange intended to face the container, along which distance (D), a waveguide is formed, forming a continuous waveguide together with the insertable waveguide part when inserted.

Abstract: A radar level gauge system is disclosed, comprising: a transmitter for transmitting pulsed measuring signals into a tank; a receiver for receiving echo signals from the tank; and processing circuitry for processing the received echo signals, said processing means including an amplifier for amplification of the received echo signals. Further, the amplifier is operable in a high and a low amplification mode, and the processing circuitry is arranged to control the amplifier intermittently in order to be in the high amplification mode only during certain time slots. By intermittently operating the amplifier in a low amplification mode, providing only a low or moderate amplification, or preferably being shut off (i.e. with essentially no amplification), the power required for the amplification could be significantly reduced. Further, the noise generated by the amplifier could be significantly reduced. A corresponding processing circuitry and operating method are also disclosed.

Abstract: A method and a system for determining a volume of a substance in a container where the method includes generating an excitation signal that creates an acoustic signal in the container, receiving the acoustic signal, and determining a volume of a substance in the container based at least in part on a signature of the acoustic signal.

Abstract: A device which detects or senses liquid level in a beverage containment vessel, and produces either light, audio or a data output based on the liquid level being equal to or less than a predetermined level. The device, in practice, preferably retains the shape of the beverage containment vessel (e.g., cylindrical), and have an outer housing of opaque or semi-translucent material. The device is either integrated into a new beverage containment vessel, or retrofitted to existing vessels. The device is powered by battery, and can be switched on, off, or into various operating modes by internal switching mechanism.

Abstract: A flooded bin measurement system is provided that includes a submarine sampler for ascending and descending within a liquid of a bin and for measuring the depth of fluid at the submarine sampler's location. In one embodiment, the submarine sampler may ascend and descend along a vertical guide based on adjustments to it buoyancy compared with the liquid in the bin, which may be controlled manually and/or automatically. The measurement system may include a bubbler system for measuring hydrostatic pressure at the submarine sampler for determining its depth within the fluid of the bin. The submarine sampler may include a device having a hollow interior, an open bottom and an air supply line connected to the hollow interior. According to a further embodiment of the invention, the submarine sampler may be fixed to a line that is connected to a counterweight at its opposite end.

Abstract: A fuel level sensor has a rotor with two magnets mounted for rotation therewith, the magnets spaced from one another and with like poles directed toward one another. A Hall effect sensor on the housing is positioned between the two magnets such that increasing the volume of fluid in the tank moves one magnet toward the sensor and decreasing the volume in the tank moves the other magnet toward the sensor. A metal sleeve around the magnets protects the parts from interference from magnetic material in the fuel. A static discharge path is provided from a metal rod connecting a float, a plate contracting the rod, and a pivot pin retaining the rotor to the housing, and a ground connector in contact with the pivot pin.

Abstract: A vibration-type angular velocity sensor realizing a suitably vibrating state of the vibrators by canceling the displacement of the vibrators caused by the gravity. The angular velocity sensor comprises base portions, vibrators coupled to the base portions, exciting means for driving and vibrating the vibrators in the x-direction, and detection means which, when an angular velocity is applied while the vibrators are being driven and vibrated, detects the angular velocity based on the vibrations of the vibrators in the y-direction at right angles with the x-direction, the angular velocity sensor further comprising position adjusting means for so adjusting the positions of the vibrators as to cancel the amount of displacement by which the vibrators are displaced by the gravity in the direction of the gravity.

Abstract: The present invention relates to apparatus and method for determining a characteristic, such as stiffness, of a log, stem, wood piece or other wood specimen. A wave generator produces a frequency varying signal which drives a transducer which is coupled to the specimen to impart a frequency varying acoustic wave into the specimen. A receiver sensor detects the resulting acoustic wave and a transmit sensor detects the output from the transducer. A characteristic response of the specimen is determined from the receiver sensor signal, transmit sensor signal and excitation signal using digital and analogue signal processing. The characteristic is determined from the characteristic response.

Abstract: An accurate measure of normally operating noise is required for a useful noise measurement system. A device is needed to make a representative measure of the boat's acoustic power using measured boat sound level with integrated corrections for sensed distance to the boat and measured ambient sound level. This device needs to make this measurement process invisible, automatic, and accurate from a law enforcement point of view.

Abstract: The claimed invention provides a blade vibration measuring system comprising a blade, a transmitter, a target with non parallel edges located on the blade shroud and a receiver. The present invention also provides a blade adapted for measuring blade vibration. Furthermore, the claimed invention provides a method for monitoring blade vibration.

Abstract: A system and method for determining the operating state of a curable composition utilizes an acoustic wave or signal transmitted into a container holding the composition. In one embodiment, characteristics of a reflected component of the acoustic signal are measured and correlated to pre-determined values indicative of one or more operating states, or degrees of curing, of the composition. In another embodiment, characteristics of a transmitted component of the acoustic signal are measured and correlated. The characteristics include, for example, the speed of sound through the curable composition or the attenuation of the acoustic signal reflected by or transmitted through the composition.

Abstract: A surface acoustic wave sensor or identification device has a piezoelectric material, and an interdigitated transducer (IDT) input/output mounted on the piezoelectric material for receiving a radio frequency (RF) signal and propagating a corresponding surface acoustic wave along a surface of the piezoelectric material. An IDT finger electrode array is mounted on the piezoelectric material and is operable to communicate with the IDT input/output for transmission of a modified RF signal from the device. The IDT finger electrode array has at least one finger electrode segment whose propagating characteristics are controlled to control the nature of the modified RF signal. A biolayer is mounted on the piezoelectric material and is associated with the finger electrode segment, and a fluidic chamber is associated with the biolayer.

Abstract: Altimeters correct themselves by analysing pressure data to identify underlying climatic changes and modify sensed pressures accordingly to provide corrected altitude values. The detected underlying climatic changes are used to provide a barometer function independent of altitude changes.

Abstract: An apparatus for producing hydrogen is able to measure a position of a interface or a surface boundary of liquids in a reaction vessel without direct contact. An apparatus for producing hydrogen by an IS process includes a reaction vessel, a first ultrasonic probe and a second ultrasonic probe. Reacting liquids are introduced to the reaction vessel. The first ultrasonic probe is provided at the bottom of the reaction vessel to detect a position of a boundary surface of the reacting liquids. The second ultrasonic probe is provided at the side wall of the reaction vessel to compensate the sound velocity.

Abstract: Differential pressure sensor systems and methods are disclosed, including an absolute pressure sensor composed of a plurality of pressure sense die for detecting sensed media, wherein each of the pressure sense die possess a back side and a front side and are respectively associated with a plurality of varying pressures. The sensed media are applied only at the backside of the pressure sense die, thereby preventing wire bonds and active regions associated with the front side of the pressure sense die from exposure to sensed media and attack from acids and abrasive chemicals associated with the sensed media.

Abstract: A capacitive pressure sensor of substantially ceramic material comprises a thick base plate (100), a front plate (140) having the same thickness as the base plate and a movable diaphragm (120) located between the front plate and the base plate. Capacitor electrodes (121b, 121a) are provided at the surface of the diaphragm facing the base plate and form a measurement capacitor. The diaphragm (120) is extremely thin and is produced by sintering a ceramic material such aluminium oxide. Owing to a pressing process used during the sintering a strong, very thin diaphragm is obtained having no mechanical stresses and fracture indications. It can be produced to have a very small thickness in order to provide pressure sensors having a high sensitivity, which can also for high-vacuum applications tolerate to be subjected to the atmospheric pressure. A shielding plate (110) can be inserted between the base plate (100) compensating the measurement capacitor.

Abstract: A direct measuring loaded gage axle assembly that measures track strength by directly measuring constant load on split axles as vertical loads are imposed by a hydraulic ram, and horizontal loads being supplied by horizontal rams through split axles and steel wheels to the railroad tracks enabling improved calibration to measure changes in track gauge indicating track strength condition and further including electronic data recording and comparison.

Abstract: The invention concerns a hydraulic expansion process for tubes. With this process it is possible to increase the number of hydraulic tube expansions that can be implemented using an expansion device. The hydraulic expansion process in accordance with the invention is highly optimized with regard to control times, pressures and flows. In this process, pressure is produced in the pressure medium with hydraulic oil via a medium separator and a pressure intensifier. In addition, the invention specifies a device for implementing the expansion process and a process for determining the maximum number of hydraulic tube expansions that can be performed with a probe. Finally, the maximum number of expansions is determined taking into account the deformations of the expanded tubes.

Abstract: To conduct a fluid, the transducer has a flow tube which in operation is vibrated by an excitation assembly and whose inlet-side and outlet-side vibrations are sensed by means of a sensor arrangement. To produce shear forces in the fluid, the flow tube is at least intermittently excited into torsional vibrations about a longitudinal flow-tube axis. The transducer further comprises a torsional vibration absorber which is fixed to the flow tube and which in operation covibrates with the torsionally vibrating flow tube, thus producing reactive torques which at least partially balance torques developed in the vibrating flow tube. One of the advantages of the transducer disclosed is that it is dynamically balanced to a large extent even in the face of variations in fluid density or viscosity.

Abstract: For conveying a fluid, the measuring transducer is equipped with a measuring tube, which is held oscillatably in a support element and vibrates during operation. The measuring tube executes, during operation, at least over part of its length, driven by an exciter arrangement, bending oscillations about an oscillation axis. These bending oscillations predominantly assume an oscillation form having at least three bending oscillation antinodes. Inlet-end and outlet-end oscillations are registered by means of a sensor arrangement. Additionally provided in the measuring transducer is a coupler arrangement connected with measuring tube and with support element and having at least one coupling element interacting mechanically, especially resiliently, with the vibrating measuring tube and the support element.

Abstract: An angular rate sensor includes: a circuit board; a package including an angular rate sensor chip and a connection terminal; and a conductive member. The angular rate sensor chip is accommodated in the package. The package is disposed on the circuit board through the conductive member. The package further includes a first electrode disposed on a bottom of the package, the first electrode connecting to the connection terminal. The circuit board includes a second electrode disposed on a top of the circuit board. The angular rate sensor chip in the package is electrically connected to the circuit board through the connection terminal, the first and the second electrodes and the conductive member. The circuit board and the package are electrically and elastically connected by the conductive member.

Abstract: The invention relates to an apparatus for measuring integrity of a fingertip of a polymeric glove. The apparatus contains a sample mount for holding the fingertip sample, a pressure supply and a pressure measuring device. The apparatus may be portable. The invention also relates to a method of measuring the integrity of a fingertip of a polymeric glove by mounting a sample on a testing apparatus, supplying pressure to the sample from an attached source and measuring the pressure required to burst the sample with a pressure measuring device. The invention also relates to a method of comparing the fingertip integrity of polymeric gloves among a set of polymeric gloves.

Abstract: A sample collector to collect samples has a chassis with a receptacle that is sized to receive a container, and a restraint positioned about the receptacle to restraint the container in the receptacle. The restraint has an open position that allows a container to be inserted into, or released from, the receptacle, and a locked position in which the container is locked in and cannot be removed from the receptacle. A controller determines a status signal, and in response to the status signal, sends to the restraint, either of (i) an open signal to set the restraint to the open position, (ii) a lock signal to set the restraint to the locked position, or (iii) a stand-by signal to maintain the open or locked position of the restraint.

Abstract: An ambient particulate sampler assembly including an upper section with a nozzle entry and an impactor nozzle housing removably receiving a single nozzle jet. A lower section is removable from the upper section and includes an impaction chamber with one or more outlets. A set of different size nozzle jets are provided and each is insertable in the impactor nozzle housing to allow the user or manufacturer to selectively choose a particular measuring criteria.

Abstract: A gas sample and conditioning device for sampling gas in a storage or transport device and conditioning the gas to avoid dew point dropout of the gas. A chamber for regulating the temperature and the pressure of the gas is provided with external A.C. or D.C. power using the leads of existing heat tracing cables to avoid the need for additional power sources to power the temperature and pressure regulating devices within the chamber.

Abstract: The invention concerns an inspection device for containers (2), that comprises a container inspection head (3) driven in alternate vertical movement via a driving member. According to the invention, the inspection head (3) has at least one driven rod (4) driven directly by friction in alternate vertical movement by the driving member (5).

Abstract: The invention relates to a transmission mechanism between at least one accessory and engine members for driving the rotor of a rotorcraft, the transmission therebetween being selectively either in isolation or in combination. An intermediate shaft is interposed between a main drive shaft for the rotor and a secondary drive shaft for the accessory, for driving the accessory from an engine member allocated to driving it. This intermediate shaft engages directly on the main shaft and meshes with an accessory drive gear via freewheels to enable the gear to be driven either by the engine member or else from the main shaft in the position for combined drive together with the rotor, the rotor being driven by the other engine member or else autorotation in the event of both engine members failing.