APPEAL FROM THE CIRCUIT COURT OF THE UNITED STATES FOR THE NORTHERN DISTRICT OF ILLINOIS.
MR. JUSTICE BROWN, after stating the case, delivered the opinion of the court.
From time immemorial wheat has been reduced to flour by grinding it between heavy disks of stone set upon a shaft, the upper one of which revolved, while the nether one remained stationary. The grain being introduced through an opening in the center of the upper stone, was ground between the burred surfaces of the stones, and gradually found its way outward, until it was discharged from the periphery or skirt of the stones in the form of flour. This ancient method has within the past twenty years given place to a system of crushing between rollers, which appears to have originated in Buda-Pesth in the kingdom of Hungary, and to have been the subject of several foreign patents. These roller mills, which, soon after their invention, were introduced into this country, and have practically superseded in all large flouring
mills the older method of grinding, consist generally of two or more pairs of rollers, mounted in a strong frame, and lying, as a rule, in the same horizontal plane. One of these rolls is fixed, and journalled in a stationary bearing. The other is mounted upon an adjustable bearing, which permits it to yield or give way in case any hard substance enters between the rollers. It is also capable of a slight vertical adjustment, to maintain the exact parallelism of the rolls. While these rolls are not in actual contact when grinding, they are very nearly so, and their adjustment is a matter of extreme nicety. That the grains of wheat may be ground to a fine powder, as well as crushed, the rolls must be slightly corrugated like the ancient burr stones, and must run at different speeds. Their action thus has the tearing effect necessary to reduce the grain to flour. The rolls must be so close together as to reduce the wheat to a fine flour, and at the same time they must not touch, or their surfaces would be ruined.
In order to secure the successful operation of these machines, provision must be made for: 1. A vertical adjustment, to bring the axes of the two rolls into the same horizontal plane, so that, in case of irregular wearing of their surfaces or bearings, the axes may be brought exactly in line. This is called the adjustment for "tram." If the adjustment were defective in this particular, the rolls would grind finer at the center than at either end, or finer at one end than at the other. 2. A horizontal grinding adjustment, by which the distance between the two rolls is kept precisely the same their entire length, while the rolls are in operation, so that they may not grind unequally at any point. 3. A spring device, by which the rolls are made to yield to a breaking strain, whenever a nail or other hard substance enters between them. 4. A stop and holding device, by which the rolls are spread apart when not in operation, and are thrown together again precisely as before, without a new adjustment. The object of the patent in suit was to provide the means for such vertical and horizontal adjustments; the requisites of such adjustments, except the third, being that they must be fixed and permanent. The object of the third was merely to prevent injury to the rolls
by the entrance of a hard substance, after the passage of which they returned immediately to their former position.
The patent contains seven claims, the second and third of which refer to the device for adjusting the rolls vertically as well as horizontally, while the fourth and fifth, which are the most material in the consideration of this case, refer to the special devices connected with the rod G for supporting the rolls.
To understand accurately the scope of the Gray invention, it is necessary to consider some of the principal foreign patents, as well as the history of the Gray patent in the Patent Office, and the limitations which were imposed by it, and accepted by him before the patent was granted. In his original application, made in July, 1879, Gray stated his invention to consist "in devices for adjusting the rolls vertically, as well as horizontally, whereby any unevenness in the wear of the rolls, or their journals or bearings, may be compensated for, and the grinding or crushing surfaces kept exactly in line;" and also "in the devices for separating the rolls when not in action," and in other details. His claims corresponded with his evident belief that he was the inventor broadly of devices for a roller adjustment, both vertical and horizontal, and were as follows:
"1. In combination with the stationary roll B, the adjustable roll C, mounted in rocking supports, the pivots of which are located in advance of the journals of the roll, substantially as described.
"2. In combination with a stationary roll, an adjustable roll mounted substantially in the manner described, whereby it may be adjusted, both vertically and horizontally.
"3. In a roller-grinding mill, a roll mounted at its ends in arms or supports arranged to be independently adjusted, both vertically and horizontally, ...