Abstract: A filtration unit is provided with a self-cleaning mechanism which backflushes a screening element therein when it becomes blinded by solid material. A reservoir enables a head of screened liquid to be built up above the screening element. Upon blinding of the screening element, a subsequent rise in the pressure at the inlet of the filtration unit is detected by way of a rising fluid level in a vertically extending chamber. The above causes the opening of a discharge valve which enables a discharge flow to rapidly empty the reservoir through the screening element in a reverse direction, thereby clearing the screen. The clearing operation is carried out entirely hydraulically by the action of the screened fluid and thus no brushes, rakes or scraping devices are required.

Abstract: A two-part vehicle safety buckle has an integral metal pressing with a flat base and overturned side walls defining a socket. A latch assembly extends around the pressing and is guided in cut-outs in the side walls and base for manual release movement generally at right angles to the base from a latch position in which a latch portion protrudes through an aperture in the base to engage a latching edge in a flat tongue received in the socket. One or more springs act between the latch assembly and the pressing or a housing. Release movement may be by direct actuation or through a pivotable or slidable release member acting on the latch assembly. A spring urged ejection member may oppose entry and assist withdrawal of the tongue, and may actuate a microswitch to indicate that an associated seat belt is in use.