Krantz Mfg. Co. v. Metropolitan Electric Mfg. Co.

286 F. 874, 1923 U.S. App. LEXIS 2774
Court of Appeals for the Second Circuit·Decided January 8, 1923·No. No. 144·Published

Opinion

MANTON, Circuit Judge.

Appellee sues for infringement of Krantz patent, No. 805,650, issued November 28, 1905. Below the patent was held valid and infringed as to claims 1, 2, and 5. The invention is for a panel board that is arranged with plug fuses and has for its object to improve the construction thereof. Theretofore fuse plug receptacles were connected with the bus bars through means of crossbars protruding from the outside of the bus bars. With the new invention here considered, the protruding crossbars are done away with, and the receptacle for the fuse plugs is placed over the bus bars, thus saving material for crossbars and space on the panel board. The inventor also does away with joints between the bus bars and the crossbars formerly leading to the receptacles. The panel board comprises a plate or base made of insulating material, such as slate or marble, contact or connection pieces for attachment to the outside and incoming electrical circuits, longitudinal conducting bars called by the trade “bus bars” which are in electrical connection with the incoming circuits, a series of contact pieces or connections for the local or distribution circuits, crossbars for making connections between the bus bars and the local -contact pieces or connections, fusible links so constructed and arranged between the bus bars and each of the local circuit terminals as to be melted and thereby open the circuit, if an excessive and dangerous electrical current is accidentally brought into the building, and receptacles for pieces, such as the ordinary screw plugs, for completing connection between any of the local circuits and the bus bars.

These elements were old and were commonly employed for many years.' In electrical distribution circuits, two kinds are known: First, the two-wire circuit, of which one wire is the positive or outgoing con[875] ductor from the generator, and the other the negative or return wire for completing the circuit back to the generator; the other, the three-wire circuit, in which there are two generators supplying the three wires, the neutral wire serving as outgoing conductor for one generator and as return conductor for the other generator, when the loads on the two generators are uneven. When the loads are equal, no current flows through the neutral wire. In the three-wire circuit, the panel board has three bus bars, while in the two-wire circuit it has two bus bars. The panel board is standardized, so that a board was sent out completed as to bus bars, cross-sections, and the like, and a man skilled in the art could make the proper connections with the outside circuit and with the electrical circuits by attaching the necessary wires to the various terminals upon the board.

Screw plugs for making electrical connection between bus bars and lateral contact pieces leading to the local consumption contacts were also standardized as to size and form. There are various forms of safety devices, but the fuse plugs are the Ones considered in this patent. The inventor pointed out the desirability and economies of construction, so far as consistent with the purpose for which the panel board is put, and also safety in construction and arrangement. By the improvement in the panel board, the amount of marble or slate in the base board and the amount of copper in the bus bars and cross-connections become less. This invention was in line with the desire or requirement of standardization, and the economy in size adapted the device for use in constricted places and is therefore practical. The essence of the invention lies in the use of’a cross-connecting piece electrically straddling one bus bar and in electrical contact with the other, in combination with the fuse plug receptacles that are located directly above the bus bars. The claims held below to have been infringed are as follows: ,

“1. In a panel board, tbe combination of bus bars, and crossbars between tbe bus bars, with fuse plug receptacles mounted upon said bus bars, and eaeb having a branch line contact piece, one of said contact pieces adapted to be electrically connected to the bus bar beneath its receptacle by a fuse plug, and another adapted to be electrically connected to a crossbar by a fuse plug, but insulated from the bus bar beneath its receptacle.
“2. In a panel board, the combination of bus bars and fuse plug receptacles mounted thereon, with a crossbar connected to one of said bus bars and passing into a receptacle on the opposite bus bar.”
“5. In a panel board, the combination of bus bars and fuse plug receptacles mounted thereover, with a cross bar connected to one of said bus bars and passing into a receptacle on the opposite bus bar, but out of contact with said bus bar, and a branch line contact piece entering said receptacle from the opposite side thereof and adapted to be put into connection with the crossbar, but insulated from the bus bar.”

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Krantz Mfg. Co. v. Metropolitan Electric Mfg. Co., 286 F. 874, 1923 U.S. App. LEXIS 2774 (2d Cir. 1923).

286 F. 874 (Krantz Mfg. Co. v. Metropolitan Electric Mfg. Co.) — published by Counsel Stack Legal Research, free access to 12M+ legal documents.