Clinton Wire-Cloth Co. v. Hendrick Manuf'g Co.

78 F. 632, 1897 U.S. App. LEXIS 2490

This text of 78 F. 632 (Clinton Wire-Cloth Co. v. Hendrick Manuf'g Co.) is published on Counsel Stack Legal Research, covering U.S. Circuit Court for the District of Western Pennsylvania primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Clinton Wire-Cloth Co. v. Hendrick Manuf'g Co., 78 F. 632, 1897 U.S. App. LEXIS 2490 (circtwdpa 1897).

Opinion

BUFFINGTON, District Judge.

This bill is filed by the Clinton Wire-Cloth Company, a corporation of the state of Massachusetts, against the Hendrick Manufacturing Company, Limited, of Carbondale, Lackawanna county, Fa., and charges infringement of letters patent. The patent involved, No. 500,508, is for a revoluble coal screen, and was issued June 27, 1893, to the complainants, as assignees of David E. Phillips. Infringement of hoth claims is charged. The case concerns the use of apparatus for screening anthracite coal. Such screens generally consist of a series of screen segments, bolted to a revoluble circular framework, built upon an inclined axle. The meshes or perforations of the segments increase in size from the upper, or inlet, to the lower, or outlet, end. By this means the smaller sizes of coal pass through the meshes at the upper end. The larger sizes pass on, and gradually leave the screen as their appropriate sized mesh is reached, until the larger sizes find exit at the lower end. Originally the screen segments used were of cast iron, but they were found objectionable for several reasons. Their great weight necessitated more powerful machinery. Where they did not correspond exactly to the contour of the framework, which was often the case from difficulties of casting, they could not be sprung ard clamped rigidly to the framework without risk of breaking. Consequently, allowance for play was necessitated. When this was provided for, or the severe action of the mine water affected the bolts and segments to the extent of allowing such play, it is obvious that the slipping of these heavy segments in two different directions, as the screen revolved, had a tendency to increase the extent, and also the severity, of the play. The consequence was the segments separated from each other, and allowed the coal to pass through the longitudinal openings thus made, instead of through the mesh interstices. Twenty or thirty years ago this imperfect screening was not material, for the smaller sizes of coal were not of commercial value, and passed to the culm pile. Of later years they have proved valuable, and the effort has been to effect their separation. For the reasons stated, cast-iron segments were not adapted to do this successfully. To meet these difficulties, wire-woven screen segments were introduced. These consisted of wire, woven to the proper sized mesh, and mounted on rigid segment frame rods, sprang or bent to conform to the curvature of the framework, to which they were, in turn, securely fastened. Obviously, such segments possessed two desirable features, lacking in the cast-iron type, — viz. lightness, and a resiliency which permitted rigid clamping to the framework. They had two weak points, however; one was the rapid disintegrating effect on the individual wires of the sulphur water, which in some regions had to be used to wash coal, and the other was that, by the continuous pounding action of the coal, the wires were liable to be displaced. When such displacement once started, subsequent use of the screen served to still further separate the wires, the desired uniformity of mesh was lost, and Imperfectly screened coal re-[634]*634suited. Thé' objections to these two types of screen were overcome by the introduction of perforated steel segments. They united the excellencies of, both the preceding forms. Their comparative lightness and resiliency gave them the desirable features of the wire-woven segment, while they preserved uniformity of mesh, openings, as well as the cast iron. They had, however, two weak points, which did not exist in the other two types. It is obvious that, as a screen revolved, the heavier pieces of coal would gather to and lie on the bottom, and thus be carried up, and slide back, in the revolution of the screen, in the same position. The result was the mesh surface was thus covered, and the finer portions above, instead of passing through their proper mesh, were carried forward on the screen, and eventually passed out with sizes of coal much larger than themselves. This objection had been overcome in-the cast-iron segments by a protuberance cast on the inner surface, which served the purpose of “tumbling” or stirring up the mass as it was carried around, and prevented its merely sliding along, in the way described. These protuberances were cast between the meshes, and did not lessen the screen surface. In wire segments this tumbling was done by the waving, undulating surface of the web itself, caused by the overlapping of the wires. This objection to the steel segment was overcome by the introduction of tumblers, but the pounding or action of the coal upon them, owing to their comparatively light weight, caused, them to sag or dip at the joints, and cause openings, through which the coal passed unscreened. Such objection was more particularly present in the earlier days of their introduction. The art was then such that small-sized holes could not be punched in heavy plates,— a difficulty overcome later. This objection was not found in the cast-iron or wire screens. While the former separated and caused longitudinal openings, as we have seen, they were too heavy to sag, and the segment frames of the wire-woven ones were so heavy and rigid they did not sag. It was to overcome these objections to the use of perforated steel segments that Phillips designed the device embodied in the patent in suit. He strengthened the segment joint and prevented sagging by bolting or riveting protector plates to the perforated abutting edges of the segments. These extended along the longitudinal edges of the segments, and covered the joints. To provide tumblers which should not cover the perforations of the segments, and thus reduce screen surface, he riveted a metallic strip upon the protector plates, or made it integral with the plates. Upon this device two claims were granted, as follows:

“(1) In a revoluble screen, a series of screen segments combined -with a flat protector plate, secured to and to connect the contiguous longitudinal edges of adjacent segments, and covering the joints between them, and an inwardly extended projection on said plate, to form a tumbler, substantially as described.
“(2) In a revoluble screen, a series of screen segments having imperforate edge, portions of, and to cover the abutting longitudinal edges of, adjacent segments, and inturned projections extended along and secured to each plate, to form a series of tumblers for the screen, substantially as described.”

It may be conceded that the screen has overcome the objections noted, has proved satisfactory, and a considerable number of them are now in use. But Phillips was by no means the first to suggest [635]*635or practice means by which- he accomplished this; and, to accord his patent its just place in the art, we must note what had been done before. In doing so, we coniine ourselves wholly to two sources of information furnished by the complainants, — viz. the statements by the patentee and by complainants’ witnesses. The patent conceded the use of tumblers was old, the objection to them, however, being their location. Thus:

“In some eases pieces of wood are bolted to the segments, the bolts extending through some of the perforations; but that is objectionable, as the tumblers «over, in the aggregate, a large number of perforations. Angle irons have also been bolted to the inside of the segments, but they are open to the same objection.”

It will thus be seen that, by Phillips’ own admissions, all he did, so far as the tumbler was concerned, was to remove.it from the middle to the edge of the screen segment. It performed no new function in its changed place.

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Cite This Page — Counsel Stack

Bluebook (online)
78 F. 632, 1897 U.S. App. LEXIS 2490, Counsel Stack Legal Research, https://law.counselstack.com/opinion/clinton-wire-cloth-co-v-hendrick-manufg-co-circtwdpa-1897.