GB313342A - Improvements in brush-holders for dynamo-electric machines - Google Patents

Abstract

313,342. General Electric Co., Ltd., and Cranston, W. M. July 9, 1928. Brush-holders. - A totally enclosed brush-holder is provided with an aperture in one side for passage of the brushes and adapted to be closed by a removable cover, and the main part of the housing member is arranged on the side of the brushway remote from the aperture whereby the brush is readily accessible through the aperture while the space above the brushway for accommodating the pressure, member and allowing the withdrawal or insertion of the brush is minimized; in addition the holder may be split so that the brushway may be adjusted for wear and a hold-off device may be provided for the brush-pressing member, this device being automatically released so that pressure is applied to the brush when the cover of the aperture is closed. Fig. 1 shows in front view a holder with the cover removed and the brush in full lines raised for removal through the front aperture and in dotted lines in its normal position. Figs. 2 and 3 show the holder in sectional side view and plan. The enclosed housing comprises a curved member 2 secured by screws 15, 16 to a front plate 3 having a brush-removal aperture 21 at its upper part, the brushway being formed by flanges 10, 11 and thickened parts 12 on the housing 2 and the lower part 18 of the plate 3. When the pressure arm 38 is raided, as shown in dotted lines in Fig. 2, the brush may be lifted from the brushway and withdrawn freely through the opening 21. Wear of the brushway may be taken up by removing the plate 3 and machining its inner surface. The aperture 21 is closed by a cover 26, Fig. 2, hinged at 27 to the housing and having flats on its hinge piece such that it will be retained either in the closed or open positions, shown in Fig. 2 in full and dotted lines respectively, by a plate spring 30 secured on its outer surface. The pressure arm 38, which turns on a shaft 37 under the action of springs 35, is coupled to the casing by a conductor 48, and is adapted to be held in its raised position by a pin 41 which runs in a bearing 14, Fig. 1, in the housing under the action of a spring 44 and engages under an extension 39 of the pressure arm. A lever 43, attached to the spring 44, enables the pin 41 to be moved by hand, but to ensure automatically that the pin shall be withdrawn and pressure applied to the brush when the cover 26 is closed, a cam 33 is provided on the cover to move the lever 43 and withdraw the pin from the extension 39 when the cover is closed. The brushholder is secured on the machine by a bracket 4 on the housing and the current connection is made through a lug 6 and clamping-screws 8 for the conductor. The degree of brush pressure may be controlled by a ratchet and pawl or like device acting on the shaft 37 and contained in a housing in the member 2.