ON BAR3ARIC AND SAVAGE LANGUAGES AND liACE NAMES. 



665 



The Automatic Balance of Reciprocating Mechanism. 

 By W. WoRBY Beaumont, M.Inst.C.JE. 



[Ordered by the General Committee to be printed in extenso among the Kepovts.] 



Vibration is often an annoying mechanical by-product representing more 

 or less waste. In connection with some questions of vibrations of build- 

 ings and structures resulting from the working of machinery, the author 

 was led to consider the possibility of the utilisation of the disturbing force 

 productive of the harmful vibration, and thereby to prevent the vibration. 

 It is senerally known that to mechanical engineers the complete balance 

 of rotary and reciprocating parts of machine, more especially those of the 

 latter kind, offer very great difficulties, and that where these are not 

 overcome vibration of the structures or framing carrying these parts is 

 set up, and is of a more or less destructive character. The balance of 

 rotating mechanism is usually only a question of care and cost, but the 

 balance of reciprocating or combined reciprocating mechanism is not so 

 easy. In steam engines, for instance, a good deal is done in the endeavour 

 to balance reciprocating parts by rotating balancing weight. This, how- 

 ever, usually only reduces but does not remove vibration, for if a balance 

 is efiected in the direction of reciprocation some disturbance is set mp in 

 a direction generally normal thereto. Mr. Tarrow has, however, suc- 

 ceeded in reducing to a minimum the vibration due to the working of 

 marine engines by opposing the motion that would otherwise occur by 

 the inertia of bob weights. The force which would be used in vibrating 

 the steamship is thus dissipated in a vertical direction, but vibratory 

 effort in a horizontal direction is still experienced. Generally, objection- 

 able vibrations in buildings, due to the working of machinery, is overcome 

 by opposing the movement which the disturbing force tends to set up by the 

 inertia of very heavy foundations. This method is often the only one that 

 can be adopted ; but there is the objection that the wear of the bearings 

 of the machinery is greater in this case than it would be if it were possible 

 to obtain perfect balance of the moving parts. In some cases the absence 

 of this balance may be rendered harmless by the permission of controlled 

 motion through small range of that, whatever it may be, to which such 

 machinery is attached. 



By way of illustration the simpler cases of vibration in the framing of 



