70 HAFID TESTING MACHINE. 



which have already been mentioned, and by means of 

 which the maximum capacity of the machine can be made 

 either 100 tons or 50 tons, as may be desired. The main 

 fulcrum upon which the beam rests is supported by four 

 cast-iron pillars, on whose inner sides are slides to guide 

 the upper and lower plates during a compression test. 

 These lour pillars, or rather their continuations, extend 

 down to a cast-iron bed placed in the basement beneath 

 the testing room floor. About half way up, or on a level 

 with the laboratory floor, is a steel-riveted girder attached 

 to the four supporting pillars, and carrying at its ends the 

 supports used in the transverse tests. 



When a test of this kind is to be carried out, a stirrup 

 is hung from the upper tension shackle ; this stirrup carries 

 a V block which rests against the under side of the beam 

 to be tested, and forms the point where the load, as 

 registered by the readings on the lever scale, is applied to 

 the beam upwards in the centre. The two ends of the 

 beam being tested rest against supports which are carried 

 by the standards at the two ends of the riveted girder. 

 These supports are attached to the ends of two hydraulic 

 rams, working downwards. 



The method of testing a beam in this machine is as 

 follows : The beam having been placed in position, the 

 poise weight is caused to move towards the long end of the 

 lever, and the load on the centre of the specimen thereby 

 increased. As the load increases, the specimen deflects, 

 and in order to take up the strain, and so keep the centre 

 of the specimen stationary and the lever floating hori- 

 zontally, water supplied under pressure from pumps and an 

 accumulator is admitted through a valve into the two 

 cylinders above the ends of the specimen. Their rams are 

 forced downwards simultaneously, and the strain taken up. 



It will be seen from the illustration that the standard 

 supporting the two-ram cylinders can be moved inwards 

 or outwards by means of racks and pinions, so that the 

 lengths of the specimens can be varied. By having the 

 direction of the specimen coinciding with the direction of 

 the main lever of the machine, beams of large span can be 

 tested on the minimum of floor space. 



37. Rapid Testing Machine. Fig. 28 shows one of the 

 latest 100-ton machines made by Messrs. Buckton. It is 

 intended for purely commercial work in tension, and is 

 designed for testing a number of specimens in rapid 

 succession. It is actuated throughout by hydraulic 



