THE EXTRACTION OF THE JUICE BY MILLS 



199 



FIG. 92 



designed in 1754 for a certain Gray in Jamaica, but not executed. 9 To 

 the mill as arranged by Collinge the trash turner, as now understood, was 

 added very early in the nineteenth century by Bell, a Barbados planter. 8 



The original form of 

 housing (which may be 

 still seen in Brazil) was 

 made of wood, the top 

 cap of the modern mill 

 being represented by the 

 massive tripartite yoke, 

 a, Fig. 84, king bolts being 

 absent, so that the system 

 in a way anticipates the 

 boltless all-steel housing 

 of recent introduction. 



The next development 

 took the form indicated 

 in Fig. 85. In this de- 

 sign the rollers were re-i 

 moved by lifting after 

 the removal of the dis- 

 tance piece. This type 

 of housing is ill adapted for resistance to the horizontal component of the 

 angular thrust, and fracture was frequent along that line, although some 

 additional security was given by the tie-rod passing through the distance 

 piece. 



Another form of housing of early date is shown in Fig. 86. This type 

 is found illustrated in early American patents, and has been made by French 

 houses, but does not ever appear to have been tried by Scotch firms. It had 

 the disadvantage that the removal of a roller necessitated the canting over 

 of one of the housings. 



Buchanan's patent (1574 of 1858) claims the form of headstock identical 



with that now generally employed. This 

 type is shown in Fig. Si, and is referred 

 to as the open-side gap type, one of the 

 patent claims being for the removal of 

 the rollers horizontally by sliding without 

 the necessity of lifting. This patent also 

 introduces the side caps, Fig. Si, bearing 

 on the brasses of the lower rollers and 

 serving to retain them in position. These 

 side caps were recessed into the housing, 

 and in Buchanan's design were secured 

 thereto by wrought-iron tie-rods or bolts 

 running in a direction parallel to the 

 direction of the axes of the rollers. 

 Buchanan's patent also claims the build- 

 ing up of the housing from wrought-iron 

 plates bolted together, but the different 

 functions of wrought and cast-iron in tension and compression in a cane mill 

 housing had been previously described by Mirrlees, in his patent, 13689 of 1851. 

 Rousselot (patent 790 of 1871) adopted Buchanan's form of housing, 



