US 2669632 A
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Feb. 16, 1954 J. HAMMERLY BUS DUCT SWITCH Filed April 16, 1949 rngy v l 1 @FIGJO 5 Inventor: Herman JHammerI by W IS At 0 Patented Feb. 16, 1954 BUS DUCT SWITCH Herman J. Hammerly, Plainville, (301111., assignor, by mes'ne assignments, to General Electric Company. a corporation of New York Application April 16, 1949', Serial No. 87.949
1 Glaim. l"
The main object to provide a. relatively small and light type of duct in which. the conductors are entirely enclosed.
Another object is to provide asystem which can be tapped by ordinary attachment plugs.
Another object is to provide receptacles for plugs which can be slid along the busway to convenient places.
Another object is to provide for convenient installation and removal of receptacles.
Another object is to provide a convenient and effective coupling between sections of the duct system.
In the form shown, the duct is formed of channel or U-shaped sections and contains a resilient insulating filler in which the conductors of splittubular form are enclosed.
The receptacle for attachment plugs are slidably mounted on the duct and have stabs or contact blades which slide on the conductors. Coupling devices connect adjacent ends of duct sections. The receptacles may be applied to the duct at the end or at pockets or vestibules arranged at intervals along the duct which are closed by coupling devices.
Fig. 1 is a perspective view of a fragment of an enclosed duct showing a coupling device and a branch receptacle for an attachment plug.
Fig. 2 is an exploded perspective view of the same parts showing the coupling device slid along the duct and the branch receptacle separate.
Fig. 3 is a cross-sectional view of the duct and showing the coupling device in place.
Fig. 4 is an end view of the insulating filler for the duct.
Fig. 5 is a sectional view showing the two main parts of the coupling device separated.
Fig. 6 is a front view of the coupling device, parts being broken away.
Fig. 7 is a perspective view of one of the grounding clips.
Fig. 8 is a perspective view of one of the coupling connectors.
Fig. 9 is an exploded perspective view of the parts of a branch receptacle.
Fig. 10 is a sectional view of a conductor or bus bar.
The casing of the duct is made up of suitable sections H], H) of U-shaped sections with a back H which may be slotted at I I to facilitate mounting on a wall or ceiling. The sides terminate in curled tracks l2, l2. The casing of the duct is grounded in any desired manner of the type Well known in the art.
The bus bars or conductors M are in the form edgel5. These conductors are made up in lengths corresponding to the length of the ductsections and are embedded in relatively softrubber fillers It. The filler recesses it" are reached through slots I"! which-are pressed together and closed when the filler is compressed in the duct. The filler is grooved at I8 to make it easy to bend the filler and thus open the slots ll, H in order to facilitate insertion of the conductors.
A receptacle is formed of two parts 2t, 26 held together by a rivet 2! or the like. Clips 22, 22 are held between the upper and lower edges of the receptacle. Each clip has an anchor 23 to connect it with the receptacle and a rear flange 2d and lug 2A to interlock with the tracks l2, l2 of the duct. Each receptacle has two stabs or contact blades 25, 25 shaped to engage and slide in the conductors l4, 14. Each stab has a contact 26 adapted to receive a prong of an attachment plug inserted through an entrance passage 27. These contacts may be of any suitable shape to accommodate any desired plug prong.
The abutting ends of the sections It, It are connected by a coupling member which has a body formed of two insulating plates 30 and 3! connected by screws 32, 32. A grounding strip 33 is mounted along each of the upper and lower edges of the coupling and each having an anchoring lug 34 held in recesses between plates 3!) and 3| and flanges 35 which interlock with the tracks 12, I2. These strips serve to bridge the ends of the tracks. The conductors l4, 14 are connected by connector strips 36, 36 which extend inwardly from the plates 3'! which anchor them in recesses between the plates 30 and 3!. These strips 36 and the anchor plates 37 are shaped so as to extend through the slots H, ii and into the mouths of the conductors 14, Hi. The ribs and grooves 38 serve to separate the grounding strips 33 from the anchor plates 31 and the rib 3-9 extends into the recess 46 to insulate the opposing anchor plates 31, 31.
A coupling member is applied to the end of each section of duct and slid in place.
When the coupling is in place as shown in Fig. 1, the ends of the conductors are electrically connected. By sliding the coupling to the position of Fig. 2, the conductors are disconnected.
The receptacles may be applied in the same manner. I prefer however to provide a cut back or vestibule 42 in the system, one or more, so that a receptacle can be inserted, into or removed from a system already installed. Such a vestibule may be provided as at 42 (Fig. 2) between adjoining sections of the duct. When this is uncovered by the coupling, a receptacle can be applied in the vestibule and slid along to the desired position of use in Fig. 1 and the coupling slid back into place to close the vestibule.
In order to form such a vestibule, the tracks and the front edges of the duct at the adjacent ends are cut away and the filler and conductors are spaced apart so as to leave room for the insertion or removal of the hooks 24, 24 and of the blades 25, 25 of a receptacle.
It will thus be seen that we have a simple, enclosed system suitable for the accommodation of conventional attachment plugs for branch take-off connectors.
In a bus duct system, a sectioned sheet metal duct of U-shaped cross section having sides that terminate in curled tracks, an insulating filler in said duct having recesses for receiving elongated split tubular conductors, said insulating filler having closed slots which connect to said recesses, said insulating filler and said split conductors of one section of duct separated by a substantial opening from the insulating filler and split conductors of another abutting duct section, said split conductors extending to but not into said opening, and a slidable coupling having flanged surrounding strips along the edge of said coupling for slidably engaging said curled track and conductor plates for slidably engaging the split conductors of the abutting duct sections, said coupling slidable to one position for covering said opening and electrically connecting the said split conductors of the abutting duct sections and to a second position for uncovering said opening and electrically isolating an abutting duct sction.
HERMAN J. HAMMERLY.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,879,198 Greis Sept. 27, 1932 1,885,513 De Mask Nov. 1, 1932 2,073,535 Kennedy Mar. 9, 1937 2,076,558 Hartmann et al Apr. 13, 1937 2,128,995 Fisher Sept. 6, 1938 2,279,383 Von Gehr Apr. 14, 1942 2,361,721 Van Deventer Oct. 31, 1944 2,399,408 Walk Apr. 30, 1946