Fig. 2329.
There are two principal kinds of connecting rods, first those in which the brasses fit in spaces provided in the solid rod, and which are known as solid-ended connecting rods, and second those in which the brasses fit in a strap secured by bolts or keys to the end of the rod. In [Fig. 2328] is shown the simplest form of solid-end connecting rod. It consists of a rod enlarged at its end to receive a brass held up to the journal by a set-screw as shown, one-half the bore being provided in the rod and one-half in the brass. The objection to this kind of rod is that as the bore wears the rod gets shorter and no means is provided to restore its length, and that during the pulling stroke of the rod the whole of the strain is concentrated on the end area of the set-screw, and this causes it to imbed in the brass, giving play to the brass unless frequent adjustment is made. It is, therefore, difficult to readily maintain a very accurate adjustment of fit with a simple set-screw of this kind. This may be to some extent remedied by the construction shown in [Fig. 2329] in which the half brass a threads upon the stem of the rod, so that when it wears shorter to the amount of half the pitch of the thread upon the rod end, the brass may be unscrewed half a turn, and the original length will be restored. The cap is held on by two screws, which may have slotted heads as shown, or screws with check-nuts to prevent the screws from slackening back, as all screws are apt to do that receive alternating strains in reverse directions.
Fig. 2330.
Fig. 2331.
