776 



HYDRAULICS AND ITS APPLICATIONS 



Avonmouth, for example, each leaf of the entrance lock gates is actuated 

 by a direct-acting hydraulic cylinder with piston and rod, the stroke being 

 12 feet 9 inches. 



The cylinder of each machine is placed in a pit at the side of the lock 

 The piston-rod is attached to a steel crosshead frame faced with gun-metal 

 and working between steel guides. The connecting-rod is of steel plate 

 of box section, and is fitted with a gimbal attachment' at each end, 

 so that a certain amount of vertical movement can take place in the gate 



Opening r*r+~* Closing 



Cooing L eV cl+38'-3\\ 



Longitudinal Secton 



Scale. 

 05 10 20 30 40 50 60 Feet 



-f Press? Stop Vaive 



FIG. 390. Hydraulic Gear for Operating Dock Caisson. 



without interfering with the action of the machinery. Control is effected 

 by valves which are operated from quay level. 



The hauling machinery for operating each of the caissons installed in 

 connection with the same dock is shown in Fig. 390, 1 and consists of two 

 cast-iron hydraulic cylinders placed side by side. The working pressure 

 is 750 Ibs. per square inch. ' The multiplying ratio is 8 to 1, and the rams 

 give a travel of the hauling rope of 66 feet per minute. One ram is used 

 for opening, and the other for closing the passage. The hauling ropes 

 are of steel wire fixed to an adjustable fast end on each cylinder, carried 

 along the centre line of the caisson under the recess cover, and attached 

 to a bracket projecting from the inner end of the caisson. Automatic 

 cut-off gear is provided to prevent over-winding at either end of the travel. 



Hydraulic Sluice Gates and Penstocks. The sluice gates, 54 inchea 



1 Figs. 390 and 391 are by courtesy of the Editor of " Engineering." 



