774 



HYDRAULICS AND ITS APPLICATIONS 



Constant Pressure 

 to Drawback. 



Discharge 



FlG. 387. Section of Cylinder and Valves of Hinged Type Riveter. 



by means of a special drawback ram which is always exposed to supply 

 pressure. The method of packing th3 rams and the general construction 



is sufficiently well indicated in the 

 figure. 



In these portable machines pres- 

 sure water is supplied to the sus- 

 pending hook by means of a 

 walking pipe, and provision is made 

 for working at a rivet at any in- 



FlG 333 clination, by means of a water- 



tight swivel joint at J (Fig. 885). 



Fig. 388 shows a design of fixed-jaw portable riveter which has the 

 advantages of a central drawback ram and a main ram with central 

 guide. 



Fig. 389 illustrates a form of fixed riveter suitable for the circum- 

 ferential joints of large boiler shells. Here both jaws of the bear are 

 fitted with rams, that to the right of the illustration being adjusted to 



