238 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. 27 



the experimental engine the connecting-rod shoes were all given their hearing 

 directly on the crank pin, as heretofore described, being held iu contact there- 

 with by means of cone nuts, which were screw-threaded to the crank pin, the 

 taper of the cones permitting adjustment for wear. This method of connecting 

 these parts to the crank pin is the usual plan of connecting three or more con- 

 necting rods to one crank pin. So much trouble had been experienced with the 

 water jackets and with minor defects in the experimental engine that no long 

 runs had been possible with it, and consequently no trouble had been experi- 

 enced because of the small amount of bearing area provided by this method of 

 joining the connecting rods to the crank pin. When, however, the new engine 

 was completed it was found that after working at high power for a few min- 

 utes the connecting-rod shoes heated so rapidly that it was impossible to run 

 the engine for more than ten or twelve minutes, the excessive heating of the 

 shoes causing a great diminution in power besides the danger of serious dam- 

 age if the tests were continued longer. At first this defect seemed almost fatal, 

 as there appeared to be no way of providing sufficient bearing area for the five 

 connecting rods on one crank pin. Happily, however, the writer was able to 

 overcome this defect by an improved design which enables all five connecting- 

 rods to operate on the one crank pin, and at the same time provides each with 

 tin' full amount of bearing area which it would have were it the only connect- 

 ing rod operating on the crank pin. This arrangement consists essentially of a 

 main connecting rod formed of a steel forging terminating in a sleeve which en- 

 circles the crank pin and is provided with a bronze lining for giving a proper hear- 

 ing surface between the connecting rod and the crank pin, both the steel sleeve and 

 the bronze lining being split, but at right angles to each other, to permit assem- 

 bling them on the crank pin. This steel sleeve, the upper half of which is formed 

 integral with the main connecting rod is rounded off to a true circle on its exterior 

 circumference, except at the point where the rod joins it. Tl ther four connect- 

 ing rods terminating in bronze shoes are then caused to hear on the exterior of 

 this sleeve, being held in contact therewith, and permitted to have a sliding motion 

 thereon sufficient to take care of the variation in angularity of the connecting 

 rods, by means of the cone nuts which are screw-threaded to the sleeve and 

 locked thereto by means of the jam nuts, as shown in the drawings. The main 

 connecting rod, of course, acts in the same wn\ as in the ordinary case where 

 each cylinder has its separate crank pin. The other four connecting rods de- 

 liver their effort to the crank pin through the sleeve in which the first connect- 

 ing rod terminates, and they, therefore, do not receive any of the rubbing effect. 

 ,\ui' to the rotation of the crank pin, except that of slipping a very short dis 

 tance over the circumference of the sleeve during each revolution, the amount. 

 of slipping depending on the angularity of the connecting rod. This improved 

 type of bearing was successful from the time of its first trial, and even in later 



