GB1469801A - Tool for screwing-up fastening members such as nuts and bolts - Google Patents

Abstract

1469801 Power operated screwing-up tools MITSUBISHI DENKI KK and TERAUCHI SEISAKUSHO KK 13 March 1974 11263/74 Heading B3N A power operated screwing-up tool such as a nut runner is provided with means for counteracting the reaction torque produced in a screwing-up operation so as to prevent its transfer to an operator, the drive is provided from a motor through bevel gears 3 and 4, a harmonic drive mechanism HD and a planetary gear system 20-25 to a holder 31 for a threaded member 32, 43 the whole drive assembly being housed in sectional casing 6, 49, 54 from the operative end of which there extends a sleeve portion 36 which shrouds the screwing-up element 31 and is provided with arms 38 for engagement with a part of the stationary fixing to which the threaded member 43 is to be attached. Alternatively the sleeve portion may be provided with an opening of elliptical or polygonal configuration which engages a corresponding washer situated beneath the member 32 being screwed-up and thereby the reaction torque is absorbed by the casing in opposition to the screwing torque provided by the socket 31. In a further embodiment the threaded fastener 43 is provided with an end projection which is adapted to shear-off when the required fastening torque is reached, spring biased ejector means 74, 73, 64 or 73, 78, 77 and 82 being provided to discharge the sheared portion out of the socket. To facilitate ease of alignment between the socket and the fastener the sleeve 36 on the end of the casing is secured thereto by co-operating recesses and projections 35b, 36a which permit a predetermined angular displacement of the anti-rotation device 38.