Hitchcock v. American Plate Glass Co.

216 F. 766, 1914 U.S. Dist. LEXIS 1638
CourtDistrict Court, W.D. Pennsylvania
DecidedSeptember 10, 1914
DocketNo. 12
StatusPublished
Cited by1 cases

This text of 216 F. 766 (Hitchcock v. American Plate Glass Co.) is published on Counsel Stack Legal Research, covering District Court, W.D. Pennsylvania primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Hitchcock v. American Plate Glass Co., 216 F. 766, 1914 U.S. Dist. LEXIS 1638 (W.D. Pa. 1914).

Opinion

ORR, District Judge.

The bill charges the defendants with infringement of certain claims of four separate patents of the United States issued to and owned by the plaintiff. These patents and the numbers of the claims alleged to be infringed are as follows: Patent No. 934,-442, dated September 21, 1909, for grinding apparatus, claims 11, 12, and 13. Patent No. 934,612, dated September 21, 1909, for grinding apparatus, claims 2 and 3. Patent No. 1,056,415, dated March 18, 1913, for apparatus for applying abrasives to grinding apparatus, claims 3, 6, 9,15, 20, and 23. Patent No. 1,056,416, dated March 18, 1913, for method of applying abrasives to grinding apparatus, claims 1, 2 and 6. The defenses relied upon as shown in the answer, are invalidity of the patents and noninfringement.

The patents and the present case have special reference to the art of grinding the surfaces of plate glass. The necessity of grinding plate glass arises 'from the fact that no known rolls which can be used to roll the molten glass into sheet form will render the glass smooth enough to take the final polish which renders it lustrous and transparent. Grinding machinery, therefore, is employed in connection with an abrasive substance, by means of which the glass is brought to an even surface. The abrasive substance in common use is sand, and the operation is successfully carried on by the use of a coarser sand at the beginning and progressively finer sands as the operation progresses, until the sheet of glass or the plate glass is ready for polishing, which is done with different substances. The glass to be ground is placed and fastened upon the surface of a round table. Above the table, and therefore above the glass, is apparatus to which is attached polishing bars, called runners, which rest loosely upon the surface of the glass. The table is whirled around at high speed, and the sand and water which are deposited on the surface of the glass are carried beneath the runners, which are rotated frictionally by the rotation of the table, and in this manner cause the sand to wear away the surface of the glass to the desired smoothness.

What has thus been briefly said is a statement, so far as it goes, of the process in use prior to the time of the application for any of the patents in suit and as it is in use to-day. The patents have to do only with the method of applying the abrasive and conserving the same for use in repeated operations.

Long prior to the application for the patents, the abrasive was used over and over again, and methods were employed for the separation of the abrasive, so that the coarser and the finer sands might be, to some extent at least, classified or graded. The method then ordinarily in use was as follows: Coarse ungraded sand was shoveled into a long V-shaped trough elevated above the table and somewhat inclined thereto, from which it was washed by means of a stream of water from a hose through a smaller trough and upon the surface of the glass upon the table. Around the table was a gutter into which the sand and water was caused to flow by the rotation of the table after it had performed its function as part of the grinding operation. From this gutter the mixture flowed into a ditch, in which were placed several barriers, over which the water and the sand suspended therein was required to flow, [768]*768but which served to trap some of the heavier and larger grains of used sand which were precipitated on the hither side of the barrier or baffle, over which the water and the smaller grains of sand flowed into the next compartment, and so on. The ditch ended in what was called the fine sand house in a long rectangular basin or pair of basins having an overflow at the end opposite that at which the sand and water entered. These precipitated sands were taken from the different compartments of the ditch and re-used in the grinding operation as required; the coarser sands being taken immediately from the ditch to the table through the V-shaped trough, while the finer sands were kept in bins to be thrown upon the table when required in the grinding operation. Hitchcock, the plaintiff, with a view to improving the methods then in use, conceived the idea of storing the successive grades of sand in suspension in a grading tank until the time for each grade to be used, and of permitting each grade to be discharged from the tank directly upon the table as required.

In his patent No. 934,442, he states, after describing the prior methods and his general purposes:

“The apparatus comprises the usual grinding mechanism in conjunction with a grading tank adapted to separate the abrading material into its various grades, and so located as to permit of its discharge to the grinding mechanism. My grading tank is so constructed that a stream of fluid passes upwardly from the tank at a constantly decreasing velocity, thereby counterbalancing the normal downward velocity of the particles of material in the tank and holding them in suspension in predetermined positions, which positions depend upon the upward velocity of the water, the frictional surface of the particles and the weight of the particles. The particles in which the ratio of the weight- to the frictional surface is largest take the lowest positions, as the normal downward velocity of a particle through the water depends upon this ratio, which ratio, in particles of the same shape and density, increases with the size of the particles. The larger and more compact particles thus come to a position of equilibrium in a stratum in the bottom of the tank, where the upward-velocity is greatest, while the other particles arrange themselves in a series of strata, the ratios of weight to resistance in liquid of the particles composing which strata decrease as the distance from the bottom of the tank increases. After the material has been graded, the contents of the tank is drawn off from the bottom, thus supplying the coarsest material to the table to do the rough grinding, and, as the surface of the glass is reduced, a finer and finer quality of material is supplied, until all the material has been withdrawn from the tank, and the plate under treatment has been reduced to the required degree of smoothness.”

His,drawings and his expressed preference in the specification contemplate a tank having the shape of an inverted cone. The sand mixed with water flows from the gutter around the table into a sump pit, from which it is forced up into the cone through its apex, and is maintained in suspension in the cone by a jet of water forced upward through the mixture. The claims of this patent relied on are as follows:

“(11) Apparatus for supplying abrasive to grinding or smoothing mechanism, comprising, in combination with a mechanism using an abrasive with water, a grading tank in position to discharge to the said mechanism, means whereby the abrasive in the tank is separated into a plurality of grades lying at different levels and ranging from coarse to fine, and connections from the tank to the grinding ‘mechanism arranged to automatically discharge the coarsest material to the grinding mechanism first, and subsequently the other grades in the order of the size of the particles comprising the grades.
“(12) Apparatus for supplying abrasive to grinding or smoothing mecha[769]*769nism, comprising, in combination with a mechanism using an abrasive with water, a grading tank .in position to discharge thereto, means for carrying abrasive in suspension to the tank, and means whereby the abrasive is maintained in suspension in the tank until discharged to the grinding mechanism.

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Related

Hitchcock v. American Plate Glass Co.
227 F. 227 (Third Circuit, 1915)

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Bluebook (online)
216 F. 766, 1914 U.S. Dist. LEXIS 1638, Counsel Stack Legal Research, https://law.counselstack.com/opinion/hitchcock-v-american-plate-glass-co-pawd-1914.