Melber v. School Dist. of Pittsburgh

243 F. 196, 156 C.C.A. 62, 1917 U.S. App. LEXIS 2108
CourtCourt of Appeals for the Third Circuit
DecidedJune 2, 1917
DocketNo. 2217
StatusPublished
Cited by1 cases

This text of 243 F. 196 (Melber v. School Dist. of Pittsburgh) is published on Counsel Stack Legal Research, covering Court of Appeals for the Third Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Melber v. School Dist. of Pittsburgh, 243 F. 196, 156 C.C.A. 62, 1917 U.S. App. LEXIS 2108 (3d Cir. 1917).

Opinion

McPHERSON, Circuit Judge.

Eetters patent Nos. 660,518 and 672,175 were issued to the plaintiff, Frederick Melber, on October 23, 1900, and April 16, 1901, respectively. The original application covered both patents and was filed August 14, 1899, but the Office called for a division, and this requirement was complied with on May 5, 1900.

[ 1 ] A few preliminary words may first be said concerning the date of the invention. In order to avoid certain references, an attempt was made to carry Melber’s date back to September 14, 1897; but we think the attempt has failed. Without discussing the plaintiff’s evidence on this subject, it is sufficient to say that these references were cited against the'applicant by the examiner, and that Melber acquiesced in his decision, without any effort to antedate the invention. In our opinion this was a virtual abandonment of the September date, and prevents the patentee from relying on it now. Maier v. Bloom (C. C.) 95 Fed. 159; rule 75, Patent Office.

[2] Both patents are for improvements in cement and steel construction. The specification of No. 660,518, aided by Figs. 1 and 2, will explain its scope:

[197]*197“My invention, generally speaking, consists in a new and improved construction, in cement, concrete, and like materials reinforced by the Introduction of metal bars, whereby the strains consequent of heavy loads are taken up and injury to the construction avoided. I am aware that it is not new to imbed metal in cement or concrete construction to strengthen the same; but such metal has heretofore been imbedded in the cement without any regard to the lines of application of the resultants of the respective strains, thus confusing the calculation of the existing strains and rendering.the accurate application of the formula of engineering impossible. These crude methods of introducing reinforcing metal also result in the requirement of a larger percentage of metal and cement than by the use of my invention. Thus the expense of manufacture is greatly increased; also many strains are thus undiscovered or unmeasured and accordingly unprovided for.
“By the use of my invention the minimum amount of cement and metal is required to produce the maximum amount of strength.
“The following is a detailed description of my invention, reference being had to the accompanying drawings, which make part of this specification:
“Figs. 1 and 2 illustrate my method of introducing the reinforcing meta}. Suppose a construction—such as a girder, slab, or post A, shown in broken elevation—to be supporting a load B, applied from above, as indicated by the arrow in the drawings. This, of course, would cause compression strains to appear above the horizontal neutrál axis B' B' and tensile strains below the same. I then calculate the tensile strains and the point of application of the resultant D, and through that point I imbed in constructing A a metal rod or bar of sufficient strength to take up and relieve the cement from the calculated resultant of the tension strains. This bar I have indicated by dotted lines m Fig. 1 and marked 1. I may also calculate the resultant of the compression strains D' and imbed through tile same rod 1' of sufficient strength to take up said strains; but, as is well known, material such as cement or concrete is able to provide for ordinary compression strains successfully without the aid of reinforcing metal. If 1 should imbed bar 1 below point D, the point of application of the resultant of compression strains would correspondingly be raised toward the top of the construction A, thus causing an enlargement of the outer fiber strains, the .limit of which is, of course, the determined factor of safety, and correspondingly if bar D were raised the point of the application of compression strains will be lowered toward the center of A. By a well-known rule of engineering, as the distance between the two points D and I)' decreased, the force applied would correspondingly increase to maintain the ‘couple,’ so larger metal rods would be required to take up Ibe increased strains. It will thus be seen that the only proper place for the rod 1 to bo imbedded is through the calculated point of application of the resultant of the tension strains—namely, Z>. The resultant of tension strains, when applied at point D, is of course equal to the sum of the Individual tension strains resulting from load B; but if the resultant were applied at any other point than point D an entirely new set of fiber strains would be produced, thus producing fiber strains at the point of the former neutral axis B' IV, and hence the formula used for calculating the strains could not be applied, and the strength of the girder would be an unknown quantity. It will be readily seen from the above that the sole point at which the metal must be placed is exactly through the points of application of the resultant of the fiber strains. In such case the exact strength of metal can be determined to take up the known resultant of the tension strains.
“To resist the calculated horizontal shearing strains, I Introduce into the construction A the'vertical metal rod 2, Fig. 2, with sufficient cross-section to resist the calculated shearing strains. The vertical shearing strains I also take up by introducing a horizontal metal rod 3 of sufficient strength to take up the calculated vertical shearing strains. I also calculate the resultants of the known vertical and horizontal shearing strains, and at right angles to said resultant I imbed a metal bar 4 4 of sufficient strength to take up the known resultant strains. As these shearing strains are computable exactly, I imbed the rods at the exact point where the strains are exerted, and thus no excess or insufficiency of reinforcement is incurred, as must necessarily be [198]*198the case where the metal is introduced without careful calculation as to the | exact position it is to be placed.
“It will readily be seen that where I have imbedded my metal rods in the material I have the equivalent of a vertical girder, 1 being the lower or tension chord, la, or, if no rod be there imbedded, the cement representing the compression chord, and the horizontal component of .rod h would transmit the horizontal shear strains as compression to the top and as tension to the bottom of the construction. ,By this method I am enabled to design the girder, slab, post, or other construction so as to avoid excess of cement or concrete by calculating the place of application and strength of strains and placing the material properly reinforced just where the load and strains consequent there* to demand.”

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Bluebook (online)
243 F. 196, 156 C.C.A. 62, 1917 U.S. App. LEXIS 2108, Counsel Stack Legal Research, https://law.counselstack.com/opinion/melber-v-school-dist-of-pittsburgh-ca3-1917.