Abstract: A reservoir for use in testing a liquid as part of a microfluidic testing system, includes a testing chamber configured to receive the liquid to be tested. A liquid inlet is fluidly coupled to the testing chamber to allow ingress of the liquid into the testing chamber. A gas outlet is fluidly coupled to the testing chamber to allow egress of gas out of the testing chamber. The gas outlet has an elevation that is higher than an elevation of the liquid inlet such that, as the testing chamber is rotated, the gas is expelled out of the testing chamber through the gas outlet, thereby reducing or preventing a presence of gas bubbles in the liquid.

Abstract: A hardness testing apparatus has an indenter shaft having an indenter at a top thereof, a force motor for moving the indenter shaft in its axial direction and applying a predetermined test force to a sample through the indenter, an external force detection section for detecting an external force applied from outside of the hardness testing apparatus to the indenter shaft when the indenter shaft is moved by the force motor, and an external force adjustment and control section for controlling the force motor to apply the predetermined test force to the sample while deadening the external force detected by the external force detection section.

Abstract: The course of torque transmitted though the driving shaft (3) between the torque generating device (1) to be tested and the driving or loading mechanism (2) is determined during an identification phase in the completely constructed test bench with the use of a rotating driving or loading mechanism (2) at pseudo-stochastic rotational speeds. Determined are thereby the parameters describing in a real and current manner the dynamic behavior of the driving shaft (3) whereby said parameters are used as an influence in further testing.

Abstract: A cylinder head gasket, interposed between a cylinder head and a cylinder block in an engine, comprises a thin metal plate having a thickness between 0.1 and 2.0 mm, and elastic insulating sheets placed on both surfaces of the thin metal plate and each having a thickness between 0.01 and 0.5 mm, in which: created is a portion at which the thin metal plate is exposed at an inner edge side extending from an inner side of the cylinder block; and also created is an extension portion extending from the cylinder block at an outer edge side extending from an outer side of the cylinder block. Also created is a combustion state detector for detecting a combustion state of an engine, wherein the cylinder head gasket is interposed between the cylinder head and the cylinder block in the engine, the portion at which the thin metal plate is exposed is at the extension portion of the cylinder head gasket, and a signal detecting device is connected thereto.

Abstract: A vacuum signal diagnostic system that diagnoses operation of a vacuum sensor of a brake booster system that is in fluid communication with an engine includes a first module that determines whether a vacuum signal of the vacuum sensor is increasing and a second module that compares an engine vacuum signal of the engine to the vacuum signal. A third module indicates a HI fault of the vacuum sensor when the vacuum sensor is increasing and a difference between the engine vacuum signal and the vacuum signal is greater than zero for a first threshold time.

Abstract: A rough road detection system for a vehicle according to the present invention includes a frequency domain module, an engine misfire module, and a rough road module. The frequency domain module converts a vector signal into a frequency domain signal. The engine misfire module determines whether an engine misfires based on the frequency domain signal. The rough road detection module determines whether the vehicle is driving on a rough road based on the frequency domain signal.

Abstract: When a fuel cut command is issued, a time required for a crankshaft of each cylinder to rotate through a certain angle is stored in one memory per cylinder. In a stage of engine production, a combustion variation per cylinder is stored in another memory. When fuel is supplied, a particular component is extracted from a value obtained by subtracting the sum of the time required for the rotation in a non-combustion state and the combustion variation from the time required for the rotation corresponding to a cylinder determined to be in a combustion stroke. The occurrence of a misfire is determined when the extracted particular component exceeds a threshold.

Abstract: A borehole logging system for the measure and the telemetry of properties and conditions of a well borehole environs. The system is embodied to measure fluids within the borehole, to measure high resolution images of the wall of the borehole, to transfer of data to and from equipment operating within the borehole environment, and to determine the status of equipment operating within the borehole. The embodiments are based upon emission, measurement and processing of electromagnetic radiation in the near infrared (NIR) region of the radiation spectrum.

Abstract: A method for determining remaining operational life of elastic cables composed of individual filaments, including establishing a fatigue curve for the cable filaments, producing a test cable from the cable material, determining the minimum breaking load of test cable sections, placing the test cable adjacent to an elastic cable, removing sections at prescribed time intervals and determining the minimum breaking load for each to form a coefficient A with reference to the original minimum breaking load of the sections and establishing an environment-dependent curve against time from all coefficients A, associating with each coefficient A a coefficient B that, for the removal time, is determined from the fatigue curve based on a load spectrum, multiplying coefficients A and B together to form reduction factors, after the test phase dismantling the elastic cable, determining its remaining strength and comparing it with the original minimum breaking load to form an actual reduction factor, forming current reductio

Abstract: An apparatus for monitoring a thickness of a film in motion. The apparatus comprises a roller for receiving and supporting the film in motion, the roller being adapted to rotate about an axis of rotation. The apparatus also comprises a position detector for detecting when the roller is in a specific angular position as the roller rotates about the axis of rotation. The apparatus further comprises a measurement unit aligned with a specific portion of the roller and coupled to the position detector. The measurement unit is responsive to a detection of the roller being in the specific angular position to measure the thickness of the film.

Abstract: The present invention relates to a method and relevant electronic device (10) for determining the hydraulic flow rate in a pump driven by a synchronous electric motor (12), said motor (12) being of the type comprising a rotor (14), equipped with a permanent magnet, which is rotation-driven by the electromagnetic field generated by a stator (16) equipped with pole pieces (18) with relevant windings. The method comprises an indirect measuring of the flow rate through the following steps of: acquiring at least one pump operation variable; -comparing the value of said variable with a predetermined correlation table to hydraulic flow rate values and determining a corresponding flow rate value.

Abstract: In a flow sensor (1) including an anticorrosion metallic diaphragm; an insulating film formed on one surface of the metallic diaphragm; and a flow rate measuring sensor formed on the insulating film, the other surface of the metallic diaphragm being in contact with a fluid under measure, between the insulating film (122) on which sensor devices (25) are formed and the metallic diaphragm, a buffer layer (121) having an intermediate linear expansion coefficient between the linear expansion coefficient of the insulating film (122) and the linear expansion coefficient of an anticorrosion metal is interposed. Thereby, the sensitivity and response of the flow sensor are improved, and also the heat resistance is improved, by which the flow sensor is made especially suitable for measuring the flow rate of a corrosive fluid.

Abstract: Described is a component for a fill level measuring device or for a pressure measuring device. The component may include a coating with a microsmooth surface so that the microsmooth surface remains essentially free of any deposits.

Abstract: A guide pipe is formed from a metal material, and its internal cross section has a circular shape whose diametric dimension gradually becomes smaller with a distance from an ultrasonic sensor. That is, the guide pipe is formed so that a route for transmitting an ultrasonic wave generated from the ultrasonic sensor may be tapered from this ultrasonic sensor toward a reflector plate. Thus, the acoustic pressure level of the ultrasonic wave which enters the reflector plate can be made higher than a value in a prior-art liquid level detecting apparatus. Accordingly, the energy of the ultrasonic wave generated from the ultrasonic sensor can be utilized for liquid level detection at a high efficiency, so that a fuel liquid level detecting apparatus capable of accurate liquid level detection can be provided.

Abstract: A liquid level sensing arrangement using a probe uses a baseline probe circuit characteristic, e.g., a circuit resistance or voltage, that is measured when the probe is out of contact with the liquid in the tank. The baseline characteristic may be used to determine a liquid level in the tank, e.g., a determination whether the liquid level is below or at/above the probe. In one embodiment, the baseline characteristic may be compared to a circuit characteristic that is measured as the tank is being filled. A difference between the baseline characteristic and the other circuit characteristic may be used to determine whether or not the probe is in contact with the liquid.

Abstract: A liquid level sensing arrangement for a tank may include a float having a disc-like shape and a sensor that detects a position of the float relative to the tank. The float may have an overall height/total displacement ratio of 0.5 or less. The float may have a range of motion relative to the tank so that at least a portion of the float may move below a portion of a bottom wall of the tank and/or below an outlet for the tank.

Abstract: The invention relates to a filling level sensor for a fuel tank 2, comprising a ceramic mounting plate 5 with a resistance network 6 arranged thereon and a contact structure 8 for the detection of an electrical filling level signal, and a cover 9 connected to the mounting plate 5, the cover 9 and the mounting plate 5 forming a housing 10. The cover 9 has at least one bead 11.

Abstract: A gyroscope that lies generally in a plane, for detecting rotation rate about a gyro input axis. The gyroscope has a substrate, and a generally planar support member flexibly coupled to the substrate such that it is capable of oscillatory motion about a drive axis that is orthogonal to the input axis. There is also a generally planar gyro member coplanar with and flexibly coupled to the support member such that it is capable of rotary oscillatory motion relative to the support member about an output axis that is orthogonal to the plane of the members. There are one or more drives for directly or indirectly oscillating the gyro member about the drive axis, and one or more gyro output sensors that detect oscillation of the gyro member about the output axis.

Abstract: The inventive device comprises a piezo element, embodied in the form of a square based rectangular parallelopiped fixed to a substrate. A piezo module matrix is embodied in a given shape. A conductive layer is made of a conductive glue. The edges of said rectangular parallelopiped are devoid of said conductive layer which is embodied in the form of a rectangle on each side face. For each side face, a charge is picked-up at one point which is located in the area of one of angular points of the conductive rectangle of the side face. The substrate is embodied such that it is conductive. The square base is fixed to the substrate by means of a conductive glue which is also used for the conductive layer.

Abstract: An activity measuring device (1) is used for recording the activity of a test subject, where the device (1) is attachable so as to be carried on the body of the test subject. According to the invention it is planned that the activity measuring device is located on a buckle (2) of a belt (3) which can be fitted to the body of the test subject, and that it has acceleration sensors (10, 10?) for detection of acceleration in all three spatial directions at right angles to each other. Furthermore, the activity measuring device (1) telemeters the recorded measurement data via a radio link to a central server (7), by virtue of the fact that the measurement data recorded by the activity measuring device (1) can be transmitted by means of a connecting cable (5) to a mobile telephone (4) via a device interface of the mobile telephone (4), which is arranged so as to be carried on the belt, and can be sent from there to the external server (7) via a radio link.

Abstract: A grammage measuring apparatus includes a dielectric resonator which is arranged only at one surface side of a sample; a shielding container with which the dielectric resonator is substantially covered except for a sample measuring surface; a microwave excitation device which causes the dielectric resonator to generate an electric field vector; a detection device which detects transmission energy or reflection energy by the dielectric resonator; a storage device in which a calibration curve indicating a resonance frequency shift amount for a grammage is stored; and a data processing device which calculates the grammage of a measuring sample from the calibration curve and measurement result of the resonance frequency shift amount of the measuring sample.

Abstract: A device and method for monitoring machine components, such as bearings, in which micro-electronic monitoring devices are provided in contact with or within the component to be monitored to acquire and transmit performance data, preferably wirelessly, to a receiving device. The acquired information, which may be accompanied by unique monitoring device identification information, may be further processed and presented to an operator in human-interpretable form. The monitoring data acquisition may be conducted over dedicated communications circuits, or may be conducted, for example, by bringing a suitable receiving device, such as a receiver-equipped PDA, within data transmission range of the monitoring devices.

Abstract: Methods are provided for using stress wave velocity measurements taken of a specimen at an early age to determine potential characteristics at a later age. The data may be used to, for example, evaluate specimens and/or families and/or clones at early ages to cut costs and/or to increase a rate of genetic gains. The specimens may be, for example, seedlings and/or explants of forestry and/or agricultural and/or horticultural species. The stress wave measurements may be obtained using conventional devices and/or systems and/or methods.

Abstract: An ultrasonic imaging device, comprising: a receiver, for receiving ultrasonic signals which carry information about human body; a processor, for analyzing and processing the received ultrasonic signals in order to get image and/or sound signals; a controller, for issuing at least one instruction; and a recorder, for recording the image and/or sound signals on recording medium in digital form in accordance with the instruction.

Abstract: Scanning probe microscopes include a probe tip coupled to a tuning fork or other acoustic resonator so as to apply a shear force when contacted to a specimen surface based on an applied acoustic signal. A secondary ultrasonic transducer is in acoustic communication with the specimen. The probe tip and the secondary ultrasonic transducer are acoustically coupled when the probe tip is in proximity to a specimen surface. Changes in resonance frequency, admittance, or other characteristic of acoustic signals coupled to the probe tip or a secondary ultrasonic transducer secured to either the specimen or the probe tip can be used in specimen imaging or to estimate probe tip placement respect to a specimen surface.

Abstract: Certain exemplary embodiments comprise a method comprising a plurality of activities comprising, for a shaft of an electric motor, the shaft comprising a runout sensing area: determining an electrical runout value for the runout sensing area; rotating the shaft; and/or heating the runout sensing area of the shaft sufficient to reduce the electrical runout value.

Abstract: Certain exemplary embodiments comprise a method comprising a plurality of activities comprising, for a shaft of an electric motor, the shaft comprising a runout sensing area: determining an electrical runout value for the runout sensing area; rotating the shaft; and/or heating the runout sensing area of the shaft sufficient to reduce the electrical runout value.

Abstract: A micromechanical pressure sensor element, in particular for tire pressure measurement. The device has at least: a layer system having a diaphragm underneath which a cavity is formed, which is separated from an external space outside the pressure sensor element; a measuring device for measuring a deflection of the diaphragm; and a seismic mass formed on, underneath, or in the diaphragm. Furthermore, in a method for using such a pressure sensor element, the pressure sensor element is operatable in a sleep mode having lower power consumption and in an operating mode having higher power consumption; in the sleep mode a change in the measuring signals of the measuring device over time is checked, and if a relevant change in the measuring signals is detected, a position change is inferred and a switchover to the operating mode is performed, in which the measuring signals of the measuring device or the analysis signals formed from the measuring signals are transmitted via a transmitter, for example, an antenna.

Abstract: An object of the invention is to provide a pressure differentiator capable of improving measurement accuracy. The pressure differentiator of the invention includes an isothermal pressure vessel 1, a narrow tube 3 for connecting an object to be measured to the inside of the vessel 1, and a differential manometer 2 for calculating a differential pressure between the object and the inside of the vessel 1. It is preferable that a flow through the narrow tube 3 during measurement is a laminar flow. The isothermal pressure vessel 1 is fitted with a temperature equalizing material. As the temperature equalizing material, thin metal wires may be used. When the pressure Ps to be measured within a vessel positioned below is changed, the pressure Pc within the isothermal pressure vessel 1 is changed, with a slight lag, through the narrow tube 3. By measuring the differential pressure Pj (=Ps?Pc) at that time, using a diaphragm-type pressure differentiator, the derivative value of the pressure Ps may be calculated.

Abstract: An ending target position Xes in which a prescribed length Ls is added to a measurement ending position Xe, a rotation rate pattern Ar for rotating a screw 2, a back pressure Ps in relation to the screw 2, and a hypothetical retraction rate pattern Ab for the screw 2 to retract, are set in advance while the remaining rotation rate pattern Ar to stop the rotation of the screw 2 at the ending target position Xes from the detected screw position X, is predicted by calculation at the time of measurement, and the rotation of the screw 2 is stopped based on the prediction. Further, the remaining retraction rate pattern Ab is predicted by calculation from the detected retraction rate Vd, and the retraction of the screw 2 is stopped based on the prediction.

Abstract: A pressure sensor for sensing a fluid pressure in a high acceleration environment. The sensor has a chamber partially defined by a non-planar membrane, the chamber containing a fluid at a reference pressure, such that the non-planar membrane deflects due to pressure differentials between the reference pressure and the fluid pressure. The deflection is converted into an output signal indicative of the fluid pressure by associated circuitry. By keeping the area of the membrane exposed to the fluid in the chamber to less than 0.1 grams, the acceleration forces have minimal affect on the amount that membrane flexes.

Abstract: A pressure sensor for detecting a pressure and for outputting a signal based on the piezoresistance effect includes a substrate having a sensor chip on one side in a thin portion and a concave portion on another side, a piezo-resistor in the sensor chip, a pedestal being attached to the substrate and having a through hole for introducing the pressure to the sensor chip and a gel material filled in the concave portion and the through hole for protecting the sensor chip. A ratio of a diameter of the through hole to a thickness of the pedestal is substantially within a range between 1 and 3.

Abstract: A device for measuring at least one property of a material sample is disclosed. The device includes at least one sensor element which is formed by a direct-write technique. The device can be an instrument for measuring strain in the sample, or for measuring other properties or attributes of a sample, such as temperature. A turbine engine disk on which components of property-measuring devices have been direct-written is also described. Methods of forming sensor elements for property-measuring devices are disclosed.

Abstract: A strain gage includes a strain gage grid of a conductive foil formed by a plurality of grid lines joined in series by end loops and first and second solder tabs electrically connected to the strain gage grid. The end loops of the strain gage are aligned off-axis with or at an angle relative to the measurement axis of the strain gage to thereby alter creep characteristics of the strain gage.

Abstract: The load on an aircraft component, such as the load on a landing gear leg during braking, is measured with a contactless, all-weather displacement measuring system. The system includes a control unit a controllable microwave emitter of electromagnetic radiation and a microwave detector comprising a plurality of antennae. When the aircraft component is subjected to a load relative movement of the emitter and detector is caused. The detector generates in response to microwave radiation received from the focused beam of radiation emitted by the emitter a signal that is received by a signal processor of the control unit. The signal received by the control unit depends on the relative positions of the emitter and detector. The control unit is arranged to provide an output signal representative of the load sustained by the aircraft component. The system may be used to control braking in dependence on the output signal so as to maximise braking efficiency without overloading the landing gear leg.

Abstract: The invention relates to a method for determining at least one mechanical parameter of at least one material in a composite system comprising at least two distinct phases, characterized in that it comprises: a) the production of at least one specimen comprising a first part of a first phase and a second part of a second phase, the second part consisting of the material to be characterized, the specimen having at least one dimension small enough to allow the strains in said specimen to be relaxed; b) the measurement, on said specimen, of at least one deformation parameter of at least said first phase, in correspondence with a plurality of points lying at different distances from an interface between said first and second phases; and c) the determination, from at least said deformation parameter, of at least one mechanical parameter of said second phase.

Abstract: The invention relates to a flow meter for liquid or gaseous media, said flow meter comprising a measuring channel through which the medium flows, at least one inlet channel and at least one outlet channel and also at least one pair of ultrasound converters for emitting and receiving ultrasound signals, wherein for guiding an ultrasound signal from one ultrasound converter to the other ultrasound converter, at least one pair of reflectors is arranged in the measuring channel, the diameter of the measuring channel is reduced using a reducer in certain regions for guiding the flow of the medium, wherein the reducer is formed by a measuring channel insert, which is arranged on and/or integrated into the measuring channel inner wall, and which is used simultaneously for holding or fixing other functional parts. Furthermore, the invention relates to a flow meter, in which a flow guide plate is used as a holding plate for the pair of reflectors and stretches in the longitudinal direction of the measuring channel.

Abstract: A method of improving the accuracy of a variable orifice flow meter that includes characterizing the flow coefficient of the flow meter orifice for different orifice openings and for different differential pressures. The method may be particularly useful with a flow metering and controlling device that includes a fluid flow conduit having at least one planar inner wall and an element having a linear edge configured to mate with the at least one planar inner wall of the fluid flow conduit. The element is movable relative to the conduit to define a flow orifice and vary a cross-sectional area of the orifice. The device also includes a processor configured to calculate the fluid flow based on the cross-sectional area of the orifice, the differential pressure, and the flow coefficient.

Abstract: The rotation angle detection device detects the rotation angle of a rotary member by employing, at the least, either a sine wave signal or a cosine wave signal that is generated as the rotary member is rotated, and employs a change per unit time in the sine wave signal or cosine wave signal to determine whether an output abnormality has occurred in the rotation angle detection device. Further, this rotation angle device is employed to detect the motor angle of an electric power steering apparatus.

Abstract: A partial flow dilution tunnel in a gas sampling system is connected to the exhaust from an internal combustion engine. More accurate gas sampling results are enabled for accounting for a delay from when the engine produces an exhaust change to when that transient arrives at a probe location. Thus, an estimated time delay is determined, and the gas sampling system is operated at least in part based upon that estimated time delay for the exhaust to arrive at the sampling location.

Abstract: A method and apparatus for inspecting the walls of an underground pipe from inside the pipe in which an inspection apparatus having a circular planar platform having a plurality of lever arms having one end pivotably attached to one side of the platform, having a pipe inspection device connected to an opposite end, and having a system for pivoting the lever arms is inserted into the underground pipe, with the inspection apparatus oriented with the planar platform disposed perpendicular to the pipe axis. The plurality of lever arms are pivoted toward the inside wall of the pipe, contacting the inside wall with each inspection device as the apparatus is conveyed along a length of the underground pipe.

Abstract: A variety of methods for operating a chromatography system are presented. Specifically, methods for operating a pumping system within a chromatography system are presented. The methods presented are directed to pumping apparatus in which very small amounts of fluid are pumped through the system. A number of techniques for detecting and compensating for leaks are presented as well as a number of techniques for operating the pumping system.

Abstract: A method and a device for testing a run-flat tire support. At least one measurement representing at least one internal or external dimension of the support representing the effective internal diameter of said support is performed. Such measurement is performed while at least one part of the radially internal surface of the support is subjected to radial centrifugal stresses.

Abstract: The invention is a method and device for determining dissolution of a solid compound within the oral cavity. The device models dissolution within the oral cavity with a flow-through cell containing a solid compound and physiological amounts of simulated saliva. The device supplies and removes the simulated saliva at rates similar to production and loss of saliva within the oral cavity. The simulated saliva interaction with the solid compound mimics saliva interaction with a solid compound within the oral cavity. Dissolution of solid compound is determined from simulated saliva collected from the flow-through cell outflow.

Abstract: A connector assembly for a planar sensing element of an exhaust gas sensor is shown, with a method for assembling. There is an opposed pair of ceramic clamshells which retain terminals, each terminal mates to corresponding contact pads of the planar sensing element. A spacer is positioned between clamshells and a seal. A retainer clip binds the ceramic clamshells. These components are contained within an upper shield, upon assembly. The spacer creates a hinge point between the clamshell devices, allowing insertion of the sensing element without abrasion or scraping of the contact pads against the terminals The retainer clip, with radially extending tabs, keeps the opposed pair of ceramic clamshells under compression upon the sensing element when assembled, due to an interference fit with the upper shield of the sensor.

Abstract: An engine starter for a radio control model includes an output shaft concentrically connected to and synchronously rotated with a T-shaped drive axle of the engine to start the engine. A drive wheel is sleeved on the output shaft for receiving an extra power. A limit wheel is sleeved on the output and synchronously rotated with the output shaft. The limit wheel is selectively driven by the drive wheel. A gear box is secured on the engine and provided to receive the output shaft, the drive wheel and the limit wheel. A torsion adjust device is mounted to a free end of the output shaft after the output shaft extending through the gear box. The drive wheel is idle running when the torsion force from the engine is greater than that from the torsion adjust device for protecting the engine from a forced operation.

Abstract: A mechanism provides compliance between a tool and a robotic arm and includes a base with a first face. The mechanism includes a post assembly with a thrust washer and a mounting post attached to the thrust washer. The thrust washer engages the first face to form a compliance joint that permits a compliance range of sliding translational motion along the first face. The mechanism comprises springs that slideably engage an outer rim surface of the post assembly and providing a compliance force resisting the sliding translational motion. A retainer is mounted to the base and compresses the thrust washer against the first face and limits rotational motion of the assembly out of a plane of the first face.

Abstract: A rack and pinion transmission is provided with a unique enveloping worm, spiral bevel or hypoid pinion in the engagement with a rack. These pinions have tapered shape which is modified by reposition of drive or/and coast face of said thread from original position. The new rack and pinion transmission is more efficient, quite and compact than conventional systems with worm or helical gear pinions. The rack and pinion transmission of the present invention is easily manufactured.

Abstract: A reversible ratchet mechanism includes a pair of roller clutches set to operate in opposite directions when engaged by a belt. During the forward motion of the ratchet assembly in either direction of propulsion of the belt, one roller clutch is disengaged while the other is engaged and locked, thereby propelling the belt. During the backward stroke, the engaged roller clutch is free to rotate. The result is that the reciprocating motion of the assembly is converted into the linear motion of the belt. The ratchet assembly includes a shift mechanism to reverse the engagement of the roller clutches and change the direction of propulsion of the belt produced by the push/pull action of the operator. The invention is advantageously used in conjunction with a wheelchair.

Abstract: A variable-speed gearbox comprises a main transmission (2) arranged in a housing (30) and a downstream range-change transmission (32), the range-change transmission having power distribution on two countershafts (12, 14). On a main shaft (4) of the main transmission (2), a gear wheel (6) is arranged in a radially movable manner which meshes with respective first gear wheels (8, 10) each on one of the countershafts. In the housing of the variable-speed gearbox, a drive output shaft (22) is radially and axially fixed which is connected a gear wheel (20) that meshes in each case with a second gear wheel (16, 18), respectively, on each of the countershafts. The gear wheel on the main shaft that meshes with the first gear wheels on the countershafts is maintained in its axial position relative to the drive output shaft by way of pressure combs (50, 52, 54, 56).