126 IMPROVED WHEEL. 



VIII. 



Description of an expanding Band Wheel to regulate thd 

 Velocity of Machinery. By Mr. Andrew Flint*. 



The relative -^^ ^^^ usual method of connecting macliinery, by a band 

 velocity of running over two wheels or riggers ; it is obvious that the 

 wrme°te7by ^^^^^ti^^ velocity of the wheels is in the inverse ratio of 

 band is not their diameters ; and these diameters always remaining the 

 variable. game, no alteration of the velocity can be obtained, but 



by a corresponding variation in that of the moving power 



applied. 



Invention of To enable the artizan io regulate the velocity of his 

 the author to ^„^v- ^ , ,, . . . 



make it so. macnmery at pleasure, the movmg power remaining as 



before, or to retain the same motion, with an alteration in 

 that of the applied force, is the purpose of the invention, the 

 models of which are now laid before the Society. In this 

 model are shewn two methods of attaining this desirable 

 object ; in both, the periphery of the band- wheel is divided 

 into any convenient number of parts, according to the size 

 of the wheels, (in this case twelve) which may be placed at 

 any given distance from the centre of the wheel, (within 

 the limits of the machinery) and thus, by enlarging the 

 , _^ circumference of one band-wheel, while the other is equally 



diminished, to alter the relative velocity of each at will. 

 These parts of the periphery, which I term V's, and are 

 marked by the letters i i i i i, &c. Plate III. are confined 

 to move in grooves, cut in the large wheels A and B, Fig, 

 I. and II. in the direction of their radii, and are moved 

 by a spiral thread in the small wheel C, which thread takes 

 in the teeth of the racks on which the V's are fixed. A 

 part of the shaft on which the wheel A is fixed, is made 

 circular, to admit the small wheel C to turn round inde- 

 pendently of the other, and thus to extend or contract the 

 racks and V's in Fig. III. — Fig, IV. is a section of part of 

 the rigger, in which the letters refer to the same parts as in 

 Fig. I. and II. 



* Society of Arts, Vol. XXIII. A premium of fifty guineas was 

 awarded for this invention. 



It^ 



