Abstract: A lever type door handle assembly adapted to be mounted on a conventional lock spindle which may or may not include a lock tumbler cylinder. The assembly comprises a handle and three inexpensively made parts which may be assembled on a lock spindle to form a rigid unit without the use of pins or screws.

Abstract: Apparatus for forming a corrugated tube from a smooth walled starting tube comprises a pair of receiving mandrels aligned spaced from each other along a preferably vertical axis and movable toward and away from each other to be engaged in opposite end portions of a starting tube. The halves of split corrugation forming discs and the halves of an end member above the uppermost of the discs, coupled together for limited movement in axial direction, are respectively carried and guided for movement in axial direction by a pair of clamping jaws tiltable between an open position permitting to align a starting tube with the mandrels and a closed position closing the split discs and the split end member and fluid tightly clamping opposite end portions of the starting tube located about said mandrels respectively between one of the mandrels and the closed end member and between the other mandrel and the clamping jaws.

Abstract: A tube end expander and a method of operating the same. The tube end expander comprises a rotatable, tubular cage defining a plurality of generally axially extending slots, and a plurality of rollers located within the cage and extending through the slots. The expander further comprises a rotatable, tapered mandrel axially extending into the cage in frictional, driving contact with inner surfaces of the rollers, and an auxiliary roller drive for transmitting rotary motion from the mandrel to the cage and rollers.

Abstract: A pair of opposed corrugating rollers (22 and 24) are supported on a frame (52) for corrugating a metal tape (20). The corrugating rollers (22 and 24) are supported for continuous reciprocating movement laterally of the tape (20) during the corrugating operation to distribute wear evenly over the surface of the rollers.

Abstract: Rolling plant for hot rolling metal workpieces comprises a reversing roughing mill, a continuous finishing mill spaced from the roughing mill and an intermediate coiler which can be retracted to an inoperative position clear of the pass-line. In the penultimate forward pass of the roughing mill, the coiler is in its inoperative position and the workpiece is rolled to a length greater than the coiler--roughing mill spacing but less than the finishing mill--roughing mill spacing, the leading end of the workpiece passing under the coiler. In the final forward pass, the coiler is in its operative position on the pass-line and effects coiling of the workpiece. Subsequently, the coil is uncoiled and led out to the finishing mill.

Abstract: A center-spine mounted tandem cantilevered rolling mill includes three or more pairs of upper and lower spindles. An elongated rigid center spine extends horizontally midway between the upper and lower spindles. The upper spindles are removably mounted above this center spine by upper front and rear bearings, with their axes extending parallel and oriented perpendicular to the length of the spine. The front ends of the upper spindles project forward centilevered beyond the spine for carrying the upper work rolls. The lower spindles are removably mounted below this center spine by lower front and rear bearings in alignment with the respective upper spindles. The front ends of the lower spindles project forward cantilevered beyond the spine for carrying the lower work rolls. Each pair of upper and lower work rolls is called a "stand".

Abstract: Two elongated gripping members (12,12) cooperate to form a closed pressure chamber about a waxed billet (61). The gripping members are reciprocated relative to an extrusion station (13), such reciprocation first moving the pressure chamber toward and past the extrusion station so as to extrude the billet through a die (66) at the extrusion station, and then returning the gripping members, in separated condition, to their initial positions to permit the immediate loading of another billet between the gripping members. Also disclosed are various additional systems, e.g.

Abstract: The invention relates to a method and a tool (6,8) for producing a bushing structure (1,2) having a bushing (1) and a polygonal flange (2) said flange initially being formed with a circular circumference (5) having an outer diameter equalling the diameter of the inscribed circle (5) of the polygon to be made whereafter by means of cold deformation the material of the flange at the location of the angles of the polygon to be made is forced to flow outwards by means of a die (8) having projections (9) the inner surfaces (10) of which are steep with respect to the axis of the die and the bottom surface (11) of which run obliquely and arching by upwards and outwards the radial width of said projections decreasing from the center to both sides.

Abstract: A constant velocity joint adapted to transmit rotary motion from a driving shaft to a driven shaft at the same angular velocity comprises, for example, an outer joint member 10 associated with the driving shaft 1, an inner joint member 20 associated with the driven shaft 2 and a plurality of ball elements 3 interposed between these joint members with a cage member therebetween. The inner member 20 has an outer spherical surface 22, and a plurality of circumferentially distributed ball grooves 21 each having its groove bottom drawing a curved or arcuate line whose curvature center is located at a point B axially apart from the curvature center 0 of the outer spherical surface as viewed in axial section. The inner member is formed through two steps of forming works consisting of a first step for providing the ball grooves and the outer peripheral surface finished to the respective shapes as desired with respect to substantially a half l.sub.

Abstract: Leakage of cooling water in means for cooling an equipment keeping a large amount of CO gas therein is detected by measuring an amount of CO dissolved in a given amount of discharged cooling water by means of a gas chromatograph. The apparatus for detecting such leakage is characterized by the combination of a sampling device, a metering device for taking up a given amount of the sample water, a degassing tank for separating CO gas and CO.sub.2 gas from water, and a gas analyzing device for quantitatively analyzing and recording the amount of CO gas dissolved in the metered sample water.

Abstract: A knock detector device for internal combustion engines comprises a first sensor for sensing the vibrations of an engine within its knocking frequency range, a second sensor for sensing the vibrations of the engine irrespective of the engine knocking frequencies, and a noise suppressing circuit for eliminating the noise in the output signal of the first sensor by means of the output signal of the second sensor.

Abstract: A system for sensing and monitoring the injection of fuel into a fuel injection type engine including a piezoelectric transducer which is affixed to a clip-on mounting for selectively attaching to the return line side of the injection nozzle to sense a vibration or shock wave and thereby generate a useful electrical signal.

Abstract: A detection unit (20) for detecting hydrocarbon gases includes a cylindrical housing (20) having a pair of opposed rectangular slots (56, 58) formed in the wall of the housing near the lower end (52). A support (60) is mounted within the housing (50) adjacent the upper end (54). A pair of baffle plates (62, 64) are mounted within the housing from the walls thereof. A semiconductor hydrocarbon gas detector (61) is mounted to the support (60) and is connected by electrical leads (30) to an analyzer and recorder (28). The detection unit (20) is mounted at the mouth of an oil or gas drilling rig and receives drilling mud into the housing (50) at the rectangular slots (56, 58) such that gases released from the drilling mud are analyzed by the gas detector (61) to determine the hydrocarbon gas content therein.

Abstract: An automated fluid flow measurement system employs two temperature sensitive silicon resistors having tracking temperature coefficients. The resistors have equal impurity concentration but different values of resistance. The first temperature sensitive resistor is employed to measure the temperature of a flowing fluid. The second temperature sensitive resistor is electrically heated to a temperature at a predetermined amount greater than the measured temperature of the fluid. Because the rate of heat transfer from the heated temperature sensitive resistor to the fluid depends upon the rate at which the fluid passes this temperature sensitive resistor, the power required in order to maintain the predetermined temperature difference in the second temperature sensitive resistor is a measure of the flow rate of the fluid.

Abstract: A generated signal is passed through an elongated signal conveying element positioned preferably perpendicular to the surface of a fluid the level of which is to be measured. The signal is directed from the signal conveying element to a detector element which senses the signal output from the signal conveying element. The signal output detected varies linearly with the depth of immersion of the signal conveying element into the fluid. In one embodiment, the signal conveying element is a capacitive probe comprising two plates or wires, one of which is grounded to the fluid into which the two plates or wires are immersed. Proper selection of accompanying circuitry results in detected signal changes which vary linearly with immersion changes. A second embodiment employs an electromagnetic wave, e.g. light, signal which passes through a light pipe signal conveying element. By nearly matching the light pipe index of refraction with that of the fluid, a predetermined percentage of the wave is lost into the fluid.

Abstract: A temperature.multidot.humidity detecting apparatus which can detect the temperature and humidity with a single element. The temperature.multidot.humidity detecting element of the present invention varies its impedance value with respect to variations in the temperature and humidity, and the temperature.multidot.humidity detecting apparatus is adapted to detect the variations in the temperature.multidot.humidity detecting element impedance to determine the temperature and humidity.

Abstract: A reversing thermometer frame adapted to be clamped to a water sampler and lowered to a predetermined depth in a body of water. The frame has a base coupled to a case containing one or more of the reversing thermometers. The thermometer case is rotatable through about 180.degree. and is biased by a torsion spring reacting between the case and the biase for rotation from a first position to a second position. A releasable latch reacts between the base and the case to latch the latter in its first position against the bias of the spring. The thermometer case is open at one end for the insertion and removal of thermometers. At the open end of the case is a closure that is linearly and rotatably movable relative to the case so as selectively to close and open the open end of the case. The connection between the case and the closure is such that the latter must move linearly a predetermined distance relative to the case before it can be rotated, thereby preventing inadvertent loss of the thermometers.

Abstract: Avionics apparatus for providing to a pilot readings of temperature, pressure altitude, and density altitude. Sensors provide electrical signals responsive to ambient temperature and pressure, and a functional module operates on signals derived from said sensors to provide signals indicative of the pressure altitude and density altitude. A multiplexer and display respond to a mode selection switch to provide visual readouts of temperature in degrees Fahrenheit and in degrees Celsius, and altitude.

Abstract: The technique for replacing certain components in a linear accelerometer with an arrangement compatible with all of the other components making up the accelerometer is disclosed herein. The components that are replaced include a potentiometer and mechanical acceleration sensing means which cooperate with one another and which operate on a DC excitation voltage for producing an initial voltage dependent on both the acceleration sensed and the excitation voltage. The arrangement replacing these latter components include acceleration sensing means operating on the same DC excitation voltage for producing an initial voltage which is dependent on the acceleration but which is independent of the excitation voltage and means for adding a percentage of the excitation voltage to this latter voltage for providing a voltage which is dependent on both the acceleration sensed and the excitation voltage, thereby making the arrangement compatible with those components in the accelerometer which have not been replaced.

Abstract: An ultrasonic diagnostic method and apparatus are provided for probing the condition in a tissue of a living body by projecting an ultrasonic beam onto the living body from a vibrator array transducer probe consisting of a plurality of tiny ultrasonic vibrators. The apparatus executes two scanning actions, of which one is a normal linear scanning that drives the ultrasonic vibrators sequentially in the manner to cause a sequential parallel shift of the ultrasonic beam substantially perpendicular to the vibrator array, and the other of which is an inclined linear scanning that drives the ultrasonic vibrators at individually different timings while sequentially shifting the driven vibrators in the manner to cause sequential parallel shift of the ultrasonic beam having an angle of inclination against the vibrator array. The images obtained through the normal linear scanning and the inclined linear scanning are combined to form a composite high-resolution image.

Abstract: A plurality of flat or curved, wedge-shaped elements form the surface of a ens of an ultrasonic inspection transducer. The multiple wedge-shaped elements permit the ultrasonic energy from the transducer to be focused (1) in a substantially straight line (line focus) parallel to the axis of the lens and (2) deflected from a plane parallel to the wedge-shaped elements and at an oblique angle to the line focus. This achieves a concentration of ultrasonic energy along a line that can be projected into material as shear waves while maintaining equidistance from the transducer's sensing wafer. This results in a concentration of ultrasonic energy that can detect small cracks in a workpiece. Further, with this lens, wider ultrasonic scan may be made with minimal errors in detection. This lens also provides accurate location information on depth of flaws.

Abstract: A method and apparatus for determining at least one component of a sample of a particulate material, such as grain or seed, on the basis of a permittivity value of the sample. Before measuring the permittivity value the sample is compacted to a predetermined degree, preferably by vibrating the sample. Preferably, the sample is vibrated while being introduced into a sample container or receptacle in which the sample is exposed to an alternating electric field for determining said permittivity value.

Abstract: A pressure transmitter manifold having a block with an inlet in communication with a pair of outlets, valve means controlling communication between the inlet and said outlets, valve controlled bleed and test connections in communication with said outlets and means for supporting said manifold block in a preselected position.

Abstract: An apparatus for inserting a thread between the testing clamps of a tensile strength testing apparatus has an insertion clamp which can travel vertically on a slide movable on a vertical rail which is also movable horizontally, whereby movement of the insertion clamp in orthogonal directions is possible. An automatic control mechanism is operable to command a drive arrangement for the insertion clamp to move the clamp along any desirable path which carries the thread to the required position in the testing apparatus.

Abstract: Apparatus for measuring the amount of previously applied torque to a fastener. A transducer is utilized to sense the amount of a subsequently applied torque to the fastener and provides an output signal representative of the applied torque. The torque is applied until further motion or breakaway of the fastener is obtained. Typically, the signal from the transducer increases until breakaway of the fastener is obtained and then the signal decreases momentarily to a valley before it again increases with further applied torque. In those instances where the particular fastener does not exhibit a well-defined valley torque signal, provision is made for detecting the value of the transducer torque signal upon breakaway. Preferably, circuitry is provided for artificially creating the valley when there is a change of slope in the torque signal above a given threshold level.

Abstract: The apparatus for the in phase coupling and uncoupling of a kinematic mechanism with respect to another such mechanism to which a stepwise rotary movement is imparted, comprises a driving toothed gear to which the stepwise rotary movement is imparted; a driven toothed gear which is to be controlled and stopped as desired in phase with respect to said driving member; intermediate drive means connected between the driving member and the driven member and movable between a first condition in which the stepwise rotary movements of the driving member are transmitted to the driven member and a second condition in which the driven member is maintained stationary. The movement of the intermediate drive means is controlled by a rotary cam.

Abstract: In a manually operable vehicle transmission a fork rod is slidably supported at both its ends by supporting holes provided in opposed transmission case walls. The fork rod is provided at its center with a shift fork for moving a coupling sleeve toward a gear to be selected. Between the surface of each supporting hole and the fork rod is interposed a ridge-shaped portion having a width which is smaller than that of the transmission case wall in the axial direction of the fork rod. The ridge-shaped portion serves to reduce resistance against the sliding movement of the fork rod.

Abstract: Disclosed herein is a device for turning over a clutch pedal which comprises an arm for turning the clutch pedal over, a rod connecting the arm to the clutch pedal for joint rotation upon working of the clutch pedal and a tension spring provided between the arm and the clutch pedal. When the clutch pedal is worked until it reaches a predetermined position, the direction of force of the tension spring acting on the clutch pedal for returning it to its initial position is changed to assist forward movement of the clutch pedal. The device further includes a means connected to the rod for applying lateral force to the rod.

Abstract: The invention is a reciprocating mechanism for use in piston driven compressors and in internal and external combustion engines. The design comprises a piston and connecting rod which is driven by a crank with an intervening transfer linkage for extending and contracting the crank radius during each revolution of the crankshaft.

Abstract: In a final drive gearing of a power transmission unit, which comprises a drive pinion shaft supported by a pair of axially spaced bearings carried on an upright partition wall of a trans-axle casing and including a pinion in mesh with a crown wheel, an abdominal cavity is provided on the partition wall to receive lubrication oil dipped up by rotation of the crown wheel, and a lateral hole is provided through the partition wall to communicate the cavity into an annular space around the drive pinion shaft between the bearings.

Abstract: A hydro-mechanical change speed mechanism of the type useful in road sweeping vehicles and the like in which the vehicle is required to travel from place to place at normal road speed but also requires the ability to travel at a relatively reduced speed while carrying out its main function such as road sweeping. The change speed mechanism herein disclosed is inserted into the normal drive train so that the input shaft 11 for the mechanism mates with the output shaft from a vehicle gear box and the output drive shaft from the mechanism 12 drives the driven wheels of the vehicle via a cardan shaft. A selector mechanism 41, 42, 43 enables the input and output shafts 11 and 12 to be mechanically directly connected together, or via respective first and second gear trains 15 and 16, to a vehicle drive pump 13 and a hydraulic motor 17 respectively. A hydraulic connection between the vehicle pump and the hydraulic motor results in an alternative hydraulic coupling between the input and output shafts 11 and 12.

Abstract: A control system for a transmission operable in high and low speed stages and adapted to change over the transmission between the two stages according to the balance of a throttle opening and vehicle speed, and to maintain the transmission at the low speed stage when throttle opening is abruptly reduced to less than a predetermined relatively small opening in order to effect engine braking when the transmission has been operating at the low speed stage.

Abstract: A portable saw chain sharpener which permits sharpening of the cutter elements of the saw chain without removal of the saw chain from the saw bar. A frame of the sharpener may be attached to the bar of a chain saw by means of a clamp which is adjustable to properly locate the sharpener with respect to chain saw bars of different thicknesses. A motor-driven rotating abrasive disc is adjustably mounted on a portion of the sharpener which is movable with respect to the frame between positions of engagement and non-engagement with saw chain cutter elements. Adjusting screws are provided to separately control bevel depth and bevel angle and to control the position of each individual cutter during sharpening thereof. A releaseable clamp permits a mounting plate to be rotated with respect to a baseplate to directly adjust abrasive wheel position for sharpening cutters at various hook and between positions for sharpening left-hand cutters and right-hand cutters.

Abstract: A main body, including a tube holding portion, a tube end squaring and deburring portion and a tool bit actuating portion, is provided with a side handle which can be gripped for support and concurrently rotated to advance the tool bit into engagement with the tube end. A conventional electrical drill rotates the tool bit and a cam converts handle rotation to tool bit advance.

Abstract: Apparatus is provided for damping a billet shears assembly and includes a damping cylinder and piston mounted to the stationary portion of the assembly opposite the moving shear blade. The damping piston defines a control cylinder and the base of the damping cylinder carries a control piston adjustably fixed in the control cylinder in axial alignment with the damping piston over the entire stroke distance. A pneumatic fluid supply line in the control piston connects the damping cylinder with the control cylinder and is provided with a non-return valve.

Abstract: A pendulum-type flying shear having a speed range of a high speed to a low speed for shearing a hot rolled material having a large cross section in which there are provided vertically movable upper and lower cutting blades within a frame mounted on a crank shaft and the blades are moved towards and away from each other to shear the material while the frame is oscillated. Particularly, while the crank shaft is rotated at a constant speed, the oscillating speed of the frame is synchronized with the speed of movement of the material to be sheared and speed synchronizing apparatus including a gear device and the like is interposed between the oscillating device and the driving device so that a good shearing performance can be obtained with a small capacity of the driving device.

Abstract: Apparatus for severing continuous lengths of hollow fibers into predetermined, equal lengths for use as chemical vapor dispensers is provided.

Abstract: A shearing device comprising a tool body or holder and a shearing edge member having at least one end with a rectangular cross section. A groove or cut-away portion having a rectangular cross section, in which the shearing edge member is fitted, is defined in the tool body. The shearing edge member is bonded or soldered to the walls of the groove at a relatively low temperature, being fitted therein.

Abstract: Most of the circuitry of an electronic organ is made up of a plurality of digital large scale integrated (LSI) circuit chips. Certain of the chips can be duplicated or substituted for others of like type to provide an organ with more or less tone generators, more or less features, etc., whereby organs of various price levels can be constructed from the same basic parts. In operation, essentially all of the organ functions and features are provided by carrying out logical and arithmetic operations on digital pulse trains generated under control of a master clock.

Abstract: A sequence generator system is disclosed for use in an electronic musical instrument wherein scanning circuits scan the instrument and produce a serial data stream corresponding to notes played on the instrument. The sequence generator system comprises sequence generating circuits responsive to the serial data stream for generating a further, predetermined data sequence and data steering circuits for receiving the serial data stream and for normally steering said serial data stream to a data output. Actuation of the system causes the data steering circuits to substitute the predetermined data sequence produced by the sequence generating circuits for the serial data stream at the data output.

Abstract: In a pick-up for an electrical musical instrument of the type including first and second pick-up assemblies positioned in parallel, spaced relationship, each of the pick-up assemblies including at least one pole piece operatively associated with the strings of the instrument and a coil wound around the pole pieces, there is disclosed an improved splitter switch whereby whether the coils are connected in series or in parallel, when single coil operation is desired, the coils are connected in series with a capacitor across one of the coils whereby the splitter switch effectively provides single coil operation without decreasing the overall signal level of the pick-up.

Abstract: A tone source circuit for electronic musical instruments which enables the selection of a desired one of a plurality of waveshapes of different duty ratios and is suitable for fabrication as an integrated circuit. The tone source circuit is composed of a tone signal generator for producing a tone signal of a frequency corresponding to each tone, a frequency divider group for frequency dividing the tone signal to a plurality of stages in a sequential order, a waveshape forming circuit for obtaining a plurality of waveshapes of different duty ratios from output signals of the frequency dividing stages of the frequency divider group and/or a feet select circuit for selecting a plurality of combinations of frequency dividing stages of the frequency divider group, waveshape select means for selecting a desired waveshape from the plurality of waveshapes of different duty ratios and means for selectively deriving a signal of the selected waveshape in response to key depression.

Abstract: A capotasto having a force plate of a length sufficient to overlie two adjacent frets on a stringed instrument's fingerboard. The capotasto's leading edge portion is adapted to press the instrument's strings against a leading fret of two adjacent frets, and the capotasto's trailing edge portion is adapted to press the instrument's strings against the trailing fret of the two adjacent frets. The capotasto's force plate may be flexible in order to generally conform to the curvature or linearity of the instrument's frets when the capotasto is clamped in place on the adjacent frets.

Abstract: A motor driven tremolo generator adapted to be connected to the pressure regulating air reservoir for a pipe organ is disclosed. The tremolo generator consists of an elongated housing pivotally mounted at one end with a free end being adapted to produce a reciprocating motion for transmission to the pressure regulator. An electric drive motor is mounted at the first end of the housing near the pivot connection, and is connected to drive a rotatable shaft located at the second, or free end of the housing. An eccentrically mounted weight is carried by the shaft so that rotation of the drive motor causes the weight to cause the free end of the housing to oscillate with respect to the pivot point. At a point generally intermediate the pivotal connection and the location of the shaft carrying the concentric weight is a suitable linking mechanism which connects the housing to the center of the bellows, whereby the reciprocating motion of the housing is transmitted to the bellows.

Abstract: A unique mounting device for a cymbal providing a quick-release arrangement. The mounting device, adapted to be secured to the free end of a cymbal stand, includes a bushing mount that is positioned on and secured to the stand, the bushing mount being adapted to receive a flexible cymbal restraint, wherein a keeper member is formed as an integral part thereof to allow the cymbal to be snapped on and off. Mounted to the restraint below the keeper member is a cymbal-support bracket having a felt pad, whereby the cymbal is held in position between the keeper member and the pad to provide positive angular positioning of the attached cymbal, and yet allow the spring to geniculate when necessary.

Abstract: A tuning aid for tuning musical instruments, particularly keyboard instruments, includes a sensor unit (12) which has an elongate capacitative sensor probe which is capable of extending across one octave of the instrument, and an octave switch (22) and a tone switch (20) on which are manually set the nominal octave and note of the string being measured. Amplifiers (16,24) including an AGC amplifier and controlled band-pass filters (18,26) are responsive to the octave and tone switches to select the measured tone. A divider (32) responsive to the octave switch divides the measured frequency by a power of two. A divider (38) is connected to the output of a crystal oscillator (36) to divide by a factor dependent upon the tone switch setting. The outputs of the two dividers are compared in a discriminator (34) which compares the two frequencies. A meter (50) displays the sense and magnitude of the discriminator output so as to display in terms of cents the amount by which the frequencies differ.

Abstract: A power-chuck actuator has an actuator body forming an axially throughgoing passage and formed centered on this axis with an annular piston displaceable axially forwardly and backwardly and having a collar projecting from the front of the actuator. This collar can be connected to the actuating element of a power chuck whose chuck body can be bolted to the front end of the actuator body. In addition the actuator body has a backwardly extending sleeve on which is carried a connector body that is normally held against rotation and that is provided with hydraulic connections for pressurizing the compartments axially flanking the piston to operate the actuator. The actuator body is provided with a fan aligned with axially throughgoing passages of the connector body so that as the two bodies rotate relative to each other air is sucked through these passages by the fan to cool the actuator.

Abstract: An improved fill piston and housing assembly for use in filling equipment is disclosed which comprises a piston disposed within an annular cavity formed by a clamped mating assembly of a mounting flange, spacer tube, guide bushing and a sealed metering cylinder section, which piston is demountably attached to an arm secured to the working means of the filling equipment by a T-shaped nut and slot.

Abstract: A swab cup for oil wells is provided which comprises means by which the elastic side walls of the cups can be radially expanded almost throughout their entire length. The oil well swab cup has a substantially cylindrical uniform wall thickness resilient annular body having a multiplicity of parallel metallic longitudinal wires imbedded in its external periphery, the lower end of each wire terminating in a hook-like formation extending into relatively free articulation with a retainer wire ring imbedded in the lower end of the body.

Abstract: A ventilation system for a vehicle is provided with a ventilation housing through which air from an outer air intake is fed to at least one air outlet opening in the vehicle passenger compartment. In the ventilation housing there is a fan which, when energized acts on the airflow through the ventilation housing. The ventilation housing is provided with an opening which allows insertion, in the transverse direction of a passage in the housing, of a filter unit, which can comprise a filter insert in a cassette and/or an evaporator in a cooling system.