772 



HYDRAULICS AND ITS APPLICATIONS 



1500 



1000 



A small lever-worked valve at the foot of the steam intensifier controls 

 the movements of a hydraulic turning cylinder T secured to the top table 

 of the press. 



ART. 205. HYDRAULIC RIVETERS. 



The hydraulic riveter provides another good illustration of the adapta- 

 bility of the hydraulic machine to workshop processes. Here the problem 

 is to get a fairly large pressure on the rivet during the first portion of the 

 ram stroke, so as to form the rivet head and to clinch the plates, and a final 

 larger pressure of the nature of an impact to cause the rivet to expand and 



fully fill its hole. The extent to which 

 this is attained in the riveter will be 

 evident from Fig. 384, which repre- 

 sents a typical pressure diagram taken 

 from the cylinder of such a machine, 

 supplied from an accumulator under a 

 pressure of 1,100 Ibs. per square inch. 

 Here A B represents the idle part of 

 the stroke during which the ram is 

 being brought up to its work, 7? C the 

 setting up the rivet and the formation 

 of the head, C D the clinching of the 

 rivet and the closing of the plates, 

 while the sudden stoppage of the 

 heavy accumulator ram is responsible 

 for a further rise in pressure D E 



above the accumulator pressure, which is depended upon to fill up the rivet 

 hole. 



One type of portable riveter is shown in Fig. 385. 1 Here the ram is 

 situated at one end and the riveting is performed at the other end of a 

 lever hinged at C. As thus arranged the machine offers some advantages 

 over the more ordinary type of bear riveter shown in Fig. 386, 1 for work 

 in restricted spaces. In the latter type the operation of riveting is 

 directly performed by the hydraulic ram, the riveter jaws being formed 

 as a single steel casting. In Fig. 387 2 a section of the cylinder and valves 

 of a riveter of the hinged type is shown. Here water is admitted to or 

 discharged from the ram cylinder by the arrangement of valves shown. 



1 By courtesy of the makers. 



2 By the courtesy of the makers, Messrs. Henry Berry & Co., Ltd., Leeds. 



FIG. 384. 



Pressure Diagram from Cylinder of 

 Hydraulic Riveter. Accumulator 

 pressure 1,100 Ibs. per square inch. 



