Abstract: A simultaneous recovery of pure benzene and pure toluene is performed by extractive distillation with N-formylmorpholine and/or other N-substituted morpholines whose substituents contain not more than seven C-atoms as a solvent. From the entry product by predistillation, a benzene fraction boiling in the region between 75.degree. and 85.degree. C. and a toluene fraction boiling in the region between 99.degree. and 111.degree. C. is separated. The benzene fraction is supplied in the lower part, and the toluene fraction is supplied in the upper part of the extractive distillation column separated by a chimney plate into two parts.

Abstract: A stripping column installation especially for separating starting materials with a high boiling point difference comprises a stripping column having a withdrawal plate and a column sump, and a circulating boiler connected with the stripping column and having a pipe bundle through which a sump product from the stripping column flows. The circulating boiler has an upper plate and a separating wall which separates a space above the upper plate into two chambers. One of the chambers has a connection for receiving the sump product from the stripping column, while the other of the chambers has a connection for discharging the sump product after heating in the boiler.

Abstract: A coupling hook (5) comprises a housing (7, 8) defining a recess (10) in which a bearing ball (12) of an implement pin (41) is received. The hook also comprises a springt-loaded locking catch (14). The catch (14) is pivotal about a bearing pin (19) with play in the direction of a first line (18) connecting the center (13) of the recess (10) to a contact point (15) between the locking catch (14) and a ball (12) in the recess (10). The coupling hook (5) also comprises a locking stop (23) engaging the locking catch (14) in an undercut recess (25) thereof to define the locking position. The size of the undercut is less than or equal to the size of the play of the catch (14) on the bearing pin (19).

Abstract: A coupling device for enabling a coupling hook to be attached with a coupling pin of a heavy agricultural implement, wherein transverse bores extend through the coupling pin and through a slip-on sleeve and a catch ball on the coupling pin with an axial securement pin extending through the aligned transverse bores, the axial securement pin having its opposite ends extending into an annular groove formed on the inner side of the catch ball aligned with the transverse bore formed therein.

Abstract: A coupling assembly particularly for a trailer hitch or similar device, wherein a coupling hook is to be engaged about a coupling sphere including an annular retainer plate having a radially innermost conical support region and a radially outermost conical guide region formed integrally with each other opening away from said coupling sphere with the support region having an opening angle of about 156.degree. and the conical guide region having an opening angle of less than 120.degree., the support region extending radially through about one-third of the total radial width of the annular retainer plate.

Abstract: A coupling device for connecting a drive shaft in a farm implement wherein a support arm is pivotally mounted at both ends thereof with the drive shaft in order to support the drive shaft in a manner which facilitates coupling thereof with a drive source. The support arm is telescopically extendable and includes a first spring connected to apply a spring force relative to pivotal motion of the support arm and a second spring applying a spring force acting longitudinally of the telescoping support arm. One end of the support arm is mounted at a point of articulation associated with the driven end of the drive shaft and the other end of the support arm is mounted at another point of articulation which is connected through a bearing with the free end of the drive shaft at which a connection is made with a drive source.

Abstract: A drive shaft assembly for providing a drive connection between the power take-off shaft of a tractor and an agricultural implement is formed in two drive shaft parts with one of the parts which is attached to the tractor joint being formed with a coupling sleeve and with the other drive shaft part which is attached to the implement to be driven being formed with a coupling hub engageable and disengageable in the coupling sleeve. The other drive shaft part is also formed with a length adjusting device comprising a pair of spring-loaded telescoping tubes arranged between the coupling hub and the end of the other drive shaft part which is attached to the implement to be driven and, as a result, the disconnecting point of the drive shaft assembly is thus located between the joint which is associated with the tractor and the length adjusting device of the other drive shaft part thereby to facilitate engagement and disengagement of the drive shaft assembly.

Abstract: A drive shaft assembly including a pair of telescoping drive shaft parts one adapted to fit within the other having a tapered member on the one drive shaft part which extends outwardly therefrom and which is retractable against the force of a spring. An introducing funnel is provided on the other drive shaft part to guide insertion of the one drive shaft part and the two drive shaft parts are formed with a profile having a generally lemon-like shape with a pair of opposed radially extending beads. The one drive shaft part is formed within the areas between said beads with an axial cutout and a guide piece is provided on the other drive shaft part for guiding the one drive shaft part into engagement therewith, the guide piece having associated therewith an introducing inclination which is directed to extend opposite to the direction of rotation of the drive shaft assembly.

Abstract: A coupling hook assembly having a hook body defining an enclosed hook pocket with a locking bolt extending from a first aperture in the hook body into operative engagement with a hook jaw to lock and unlock an implement pin for joining a trailer with an agricultural tractor. The locking bolt is pivotally connected with an operating lever mounted on a fixed pivot within the hook body and extending through a second aperture therein. A yoke pivotally mounted on the operating lever is adapted to engage with a notch formed on the external surface of the hook body to secure the locking bolt in the locked position or into engagement with a recess in a part of the operating lever to secure the coupling hook assembly in the unlocked position.

Abstract: A three-point tractor hitch system includes a coupling hook structure as the upper link thereof formed with a hook body defining a concave recess for receiving therein in locking engagement a coupling sphere. A locking bolt received within a rectilinear opening extends into the concave recess of the hook body with a curved locking surface adapted to engage the contour of the coupling sphere. The locking bolt is pivotally mounted at its opposite end to a control lever having a generally U-shaped recess formed therein to engage a bearing pin mounted on the hook body. The U-shaped recess has lateral sides arranged so that imaginary extensions thereof will intersect the axis of the locking bolt and bearing means are interposed between the control lever and the hook body on a side of the pivotal coupling of the locking bolt to the hook body opposite the side on which the U-shaped recess is formed.