Abstract: A locking structure for a spring-loaded, pushbutton pin coupler, the inveon prevents inadvertent or accidental depression of a "button latch" pin which can result in an uncoupled joint. The present locking structure cooperates with a pushbutton pin connector such as is commonly used on collapsible or extendible arms or legs. According to the invention, a conventional button latch pin is provided with a locking plate at its inner end, rotation of the pin after coupling of joint with the pin causes the locking plate to also rotate into engagement with a fixed pin element carried by the structure coupled by the pin, thereby preventing displacement of the pin from the locked position.

Abstract: Road safety guardrails are constituted by vertical wooden posts carrying at least one horizontal rail made up of wooden logs which are connected end-to-end by pairs of metal straps which are interconnected by bolts, each passing through both straps and one or other of the logs. Each inter-log connection is reinforced by incorporating metal rods that run through each log and intersect the diametrical plane containing the bolts for interconnecting the straps.

Abstract: An elongate safety conduit or trench for receiving chemical liquids, having first and second preassembled conduit elements, the first located and retained within the second. A space is between the two at the bottom for collecting liquid that may leak through the first. A seal along the length of the conduit between the two elements inhibits entry of liquid between the two.

Abstract: A bracing system is disclosed which is particularly suitable for providing line and end corner bracing for "T-post" fence construction. The bracing system comprises slidable collars which are positioned over the posts and located vertically between the lugs at a desired location. A wedging arrangement is used to secure the collar between adjacent lugs on the posts, and the collar has provisions for accepting accessories to permit a rigid cross-brace, typically also another "T-post", to be inserted therebetween for providing rigid cross-bracing between adjacent "T-posts" of the fence. Accessories also are disclosed to adapt the posts for uses other than fences.