It has become the practice to strengthen the stiles of a ladder in at least the region of the lowermost step by providing braces. Typically, the stiles are of U-shaped channel construction where the ladder is made of metal such as aluminum. Each stile had a flat metal strip extending upwardly at an angle from each side flange of the channel section terminating at a respective side edge of the step. The strips were riveted or otherwise secured to the stile and the step. Thus each stile had a pair of braces.
U.S. Pat. No. 2,126,171 illustrates this general arrangement except that the braces extend between the stiles and the second lowermost step and only one brace is associated with each stile.
U.S. Pat. No. 3,009,535 discloses a similar brace configuration.
Such brace configurations are considered undesirable for at least two reasons. These configurations result in a converging space between the brace and stile. Whilst not recommended, users sometimes use the ladder without footwear and should they mis-step or slip from the ladder the converging space has been known to cause the severing of toes. Where such braces are employed higher up the stile there have been instances of the user's fingers being severed.
In addition, such braces have been found deficient in the strength provided and fail in a manner called "fold under" where an impact load caused by the user falling and landing onto the lowermost step is applied to the step. Such failure causes the stiles in the region below the lowermost step to bend. The stiles both typically fold in the same direction with one folding under the ladder and the other folding outwardly and finishing laterally outwardly of the ladder. Typically ladders may be subjected to 1.2KN and should not fail in this way to be acceptable.
The ladder of U.S. Pat. No. 4,204,587 is provided with a brace extending between the side flanges of the channel shaped stile and is secured to the web of that channel and the underside of the lowermost step. The material of the brace is substantial but nevertheless this construction can still result in the severing of toes in the case of the user falling from the ladder.
U.S. Pat. No. 3,083,786 discloses braces in the form of pairs of gusset plates. Whilst this construction does not lead to severing of toes should the user fall, the construction was not sufficiently strong and fold under failure was still possible. Such failure can lead to product liability claims and insurance to guard against this contingency results in insurance costs being reflected in higher initial ladder purchase prices.
In most ladder constructions separate non-skid feet like that shown in FIG. 7 of U.S. Pat. No. 3,083,786 were present and separately fitted to the lowermost end of each stile. This was an added stage in the manufacturing process and added to the eventual cost of the ladder.