382 



THE INDIA RUBBER WORLD 



[September i, 1907. 



THE "P. B." DYNAMOMETER. 



WITH tlie idea that a field exists for the better mechanical 

 testing of india-rul)bcr, woven threads, and some other 

 substances and fabrics, a French inventor has developed an 

 apparatus which he has termed a dynamometer, which has been 



tongue moves, to which a marked weight may be suspended. 

 This lever is supported on a vertical rod accurately guided in the 

 column, and on its lower part this rod carries a pillow which 

 presses on the piece to be abraded (see Fig. 3). The dynamome- 

 ter has been brought out by A. D. Cillard fils, 49, Rue des 

 Vinaigriers, Paris, who may be addressed also at No. 27 West 

 Thirty-third street, New York. 



SOLE AND HEEL STAMPING 

 MACHINE. 



THE 

 of 



a. sttx'l sprinj;; 



dial; /. 

 , screw; 



puintLr; e, jaw attaclicii to spring; f. movable jaw 

 o, g, headstocks; q, icc iitric rod. 



Dynamometer for Testing RrmJER, 



J^ 



r^ 3 



z 



patented in various countries and is designated in France by tlic 

 trade mark "P. B." Chemical tests, while always interesting and 

 in many cases of value, do not suffice for every purpose. In by 



far tlie majority of cases 

 the articles in rubber, for 

 (-■-\amplc, supplied by fac- 

 tories to their customers 

 are subjected in use chiefly 

 to mechanical strains, and 

 it is desirable that the 

 manufacturers should be 

 able to satisfy themselves 

 that the articles are adapt- 

 s for this purpose that this dyna- 



a> 



5^ 



E machine illustrated here consists 

 f a cast iron framework on which 

 is mounted and fixed a wood table .? 

 inches thick, 42 inches wide and 39 

 inches long, the framework being well 

 braced together and arranged to support 

 standards and the mechanism under the 

 table. The mechanism consists of a 

 driving shaft with fast and loose pulleys 

 running at about 100 revolutions per 

 minute with pinion gearing into a large 

 wheel fixed on a counter shaft. The 

 driving puUej'S are provided with belt 

 shifting arrangements capable of being 

 actuated either at the back or front of 

 the machine. The counter shaft men- 

 tioned is fitted with a balanced flywheel 

 as well as the large spur wheel, and 

 two cranks of disc pattern, one at each 

 1 which connecting rods of mild steel are 

 working in vertical guides above the tabic. 

 Tliis slide or crosshead is provided with tw-o adjustable stampers 

 for pressing on to the dies placed ujion the material being cut by 

 hand. The dies must be moved by hand to a new position be- 

 tween the stamper rising and falling again. The rubber must" be 

 brought on to the table, but it is advisable to put wood blocks 

 underneath where the dies are placed, so as to prevent cutting of 

 the table top. The table is not removable in itself, but the blocks 

 are changeable or removable at will. With respect to the amount 

 of work that this machine can do. assuming that the shaft runs 



e.fl . r Ihe 

 taken uji ti 



-jatt 

 the : 



1.-.;: 

 aide 



Dv.\.\MO.\i_. 



It 



ed to support the strains 

 mometer has been devised. 



The "P. B." dynamometer, as indicated by Fig. i and Fig. 2 in 

 the accompanying illustrations, is horizontal. It consists of a 

 solid cast iron table, faced perfectly true in its upper part, resting 

 on strong cast iron legs, stiffened by cross stays. On this table 

 are the two principal parts of the dynamometer : the apparatus 

 producing the stresses and the appliance for measuring them. 



The table is provided with a horizontal spring balance, which 

 carries one of the jaws to hold the test piece. Means are pro- 

 vided to recalibrate the spring, and the pointer is arranged so 

 as to remain at the ma.ximum indication on the breakage of a 

 specimen, thus recording the breaking load. The load is applied 

 either with a hand wheel and bevel gear for quick motion, or 

 through worm gear for heavy loads at low speed, and pulsating 

 stresses of any desired amplitude can be applied by means of an 

 eccentric gear at adjustable speeds. Samples can be tested in a 

 bath, by means of which the temperature can be varied, and the 

 apparatus also provides for compression, plasticity, repeated 

 bendings, wear and friction tests, so that it is capable of being 

 applied to a large number of purposes. 



One of the important features of the P. B. system relates to 

 the possibility of determining by its aid both the wear and tear 

 and the coefficient of friction of rubber, fabric and so on. On 

 the table of the dynamometer a small column is placed, carrying 

 a graduated double arm lever arrangement along which an index 



4 





Sole .^nd HEEr. Stampint: M.\rrTTXE. 



