484 REPORT — 1886. 



The Sphere and Roller Mechanism for Transmitting Power. 

 By Professor Hele Shaw and Edward Shaw. 



[A communication ordered by the General Committee to be printed i» extenso' 



among the Reports.] 



[Plates VIII. and IX.] 



A PAPER was read by Pi'ofessor Hele Shaw before Section A at the- 

 Montreal meeting of the British Association, in which the principle of the 

 ' sphere and roller ' mechanism was explained, and certain applications of 

 it suggested (see p. 631, Report for 1884). A subsequent paper on the 

 ' sphere and roller ' friction gear was read last year before Section G at 

 Aberdeen (see p. 1193, Report for 1885). The latter paper gave the 

 results of actual trial of the mechanism, and described a machine for 

 transmitting 2 H.P., but it specially dealt with the modes of obviating 

 the various difficulties experienced in the course of bringing the mechan- 

 ism into practical operation. 



Since that time Mr. Edward Shaw has been engaged in the develop- 

 ment of the mechanism, and the present paper contains (1 ) a brief descrip- 

 tion of the various machines constructed since the reading of the previous 

 papers ; (2) an account of certain details of construction which have been 

 introduced in these machines in order to meet novel difficulties ; (3) cer- 

 tain data derived from actual work and from special experiments by both 

 the authors in connection with points concerning which little appears to- 

 have been previously known. 



Although a complete account of the theory of the mechanism for 

 mathematical purposes has been published in the ' Philosophical Trans- 

 actions of the Royal Society ' (Part II. 1885), and a new machine exhibited 

 at the Inventions Exhibition has been described and illustrated (' Engi- 

 neering,' 1885), yet so much new work has been done in designing and 

 testing the machines since made that the authors believe the following 

 account of the results will prove of interest and value, especially as the 

 question of friction gearing is one about which few facts are published, 

 and much uncertainty exists as to proper proportions of surfaces in 

 contact, dimensions of the various working parts, power transmitted, and 

 actual loss in its transmission. 



1. Description of Machines. 



In the first two machines made for the transmission of power, the weight 

 of the ball was utilised for obtaining pressure on the rolling surfaces. 



In one of these the driving and driven surfaces of the wheels were of 

 cast iron ; in the other oak was tried, which proved to be useless owing to 

 its distortion, and secondly raw hide, which was found not sufficiently 

 rigid for the pressures required. Neither machine was of any use, the 

 efficiency being too small. Their failure was due both to the smallness 

 of the pressures and the vibration set up, which latter kept the ball 

 away from the wheels. 



The next machine ' was designed so that any required pressure could 

 be brought to bear on the rolling surfaces, and which, while trans- 

 mitting considerable force, should not occupy much space. The diameter 



' For a full account with illustration see Engineering, Nov. 27, 1885. This machine 

 is now on loan at the South Kensington Museum. 



