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

286 F. 874, 1923 U.S. App. LEXIS 2774
CourtCourt of Appeals for the Second Circuit
DecidedJanuary 8, 1923
DocketNo. 144
StatusPublished

This text of 286 F. 874 (Krantz Mfg. Co. v. Metropolitan Electric Mfg. Co.) is published on Counsel Stack Legal Research, covering Court of Appeals for the Second Circuit primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

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

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]*875ductor 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.”

The inventor did not limit himself to the precise details of construction shown in the drawings or specifications as to the receptacle or panel board, but the construction is referred to as follows: The recep-' tacles are made of porcelain or other insulating material, and inside of each is put a conducting metal screw shell F, properly treaded to receive the screw plug G that contains the fuse. By running a short bent [876]*876contact piece D from the local circuit terminal to the contact screw, shell F, that terminal will be in electrical contact with the screw plug G, when the same is inserted in the shell F. The receptacle C is mounted directly above the bus bar B, the screw shell F is maintained at a considerable distance above the bus bar B, and hence, when the screw plug G is in place, it is quite out of contact with the bus bar; hence the circuit is not completed by contact of the screw plug G with the bus bar. To the left of Figure 3, there is shown a contact screw B projecting down from the upper part of the receptacle and engaging with the bus bar immediately beneath it, but insulated from the contact piece D by an air space or opening d, so as to be out of direct contact with the latter. By this means the circuit is completed from bus bar B1, up through the contact screw L, to the screw plug G, through the fuse contained in the latter to the screw shell F, thence through tíre lateral contact piece D to the local circuit terminal at the left. The receptacle C has openings at either side, one for the entrance of the contact piece D, the other for entrance of “a connecting piece B,” which is in direct contact with the bus bar B, and extends laterally therefrom across through an opening in the opposite shell or receptacle C1, where it is fastened firmly in position by a contact screw Ip, which holds it in position above, but out of electrical contact with, the second bus bar B1; it being maintained in firm mechanical union therewith (though out of electrical contact) by the screw B1 which projects downward from the right-hand screw shell F1, which latter screw extends to a layer of insulation that overlies the right-hand bus bar B. In mechanical and electrical arrangement the right-hand receptacle C1 is similar to the left-hand one, except that the shortness of the contact screw Bx, a layer of insulation above the right-hand bus bar B,

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Bluebook (online)
286 F. 874, 1923 U.S. App. LEXIS 2774, Counsel Stack Legal Research, https://law.counselstack.com/opinion/krantz-mfg-co-v-metropolitan-electric-mfg-co-ca2-1923.