Fig. 31. A Typical Cross-head
The points to be brought out in connection with the cross-head are the methods of alignment and adjustment. A typical cross-head is shown in cross and longitudinal sections in [Fig. 31]. Alignment in a straight line, longitudinally, is secured by the cylindrical form of the bearing surfaces or shoes, shown at S. These are sometimes made V-shaped in order to secure the same result. The wear on a cross-head comes on the surfaces S, and is taken up by the use of screw wedges W, shown in the longitudinal section. As the sliding surfaces become worn, the wedges are forced in slightly by screwing in the set-screws and clamping them in place by means of the check-nuts.
Figs. 32 and 33. Methods Commonly Used for Taking Up Wear in a Connecting-rod
The method commonly employed in taking up the wear in a connecting-rod is shown in [Figs. 32] and [33]. The wear at the wrist-pin is taken by the so called brasses, shown at B in the illustrations. The inner brass, in both cases, fits in a suitable groove, and is held stationary when once in place. The outer brass is adjustable, being forced toward the wrist-pin by a sliding wedge which is operated by one or more set-screws. In [Fig. 32] the wedge is held in a vertical position, and is adjusted by two screws as shown. The arrangement made use of in [Fig. 33] has the wedge passing through the rod in a horizontal position, and adjusted by means of a single screw, as shown in the lower view. With the arrangements shown, tightening up the brasses shortens the length of the rod. In practice the wedges at each end of the rod are so placed that tightening one shortens the rod, and tightening the other lengthens it, the total effect being to keep the connecting-rod at its original length.
| Fig. 34. Outboard Bearing for Corliss Type Engine | Fig. 35. Inner Bearing and Bed of Corliss Engine |