The granite rollers at a1, a2, a3 are fitted with an octagonal iron axle that is somewhat thicker at the interior part and they are mounted upon a frame as shown in the drawing. The sockets of the central rollers a2 are fixed and each one is held in position by three sets screws; those of the two other rollers can be shifted along grooves in the frame and when the cylinders a1 and a3 have been brought into proper position relatively to the cylinder a2 they are held fast by the set screws p.
Fig. 35.
Fig. 36.
For the purpose of this adjustment, there is at each end of the machine a horizontal wrought iron shaft f that can be turned by the winch e, and these shafts are fitted with two endless screws d working in the corresponding wheels c. These occur on the spindles a, which screw in and out of the bearing blocks of the rollers a1 and a2, but turn only in the fixed collars b without being shifted from their place. The result is that on turning the cranks e the corresponding cylinder a1 or a3 is moved nearer to, or further from, the central cylinder a2, while the position of all of them always remains parallel. The shaft Q is set in motion by the driving wheel L fitted with the loose wheel L1. It acts first upon the cog wheel K which works in the larger wheel J on the axle of the central roller a2. That works in the cog wheel O and the wheel P fitted to the roller a1 driving them as well as the wheel M and the pinion N of the roller a3 The result is that the axle a2 makes 1¾ revolutions and a3 6-1/8 revolutions while a1 in the same time makes only one revolution.
Fig. 37.
The cacao or chocolate is supplied to this machine by the hopper R which is placed between the rollers a1 and a2. The pasty mass adhering to the rollers is carried forward by the quicker moving roller a2 and it is ground finer between the rollers a2 and a3, after which the material is removed from a3 at the outer side by an adjustable blade gg and then falls down into a receptacle below.
