GB1369007A - Electric motor and subframe assembly for a power tool - Google Patents

Abstract

1369007 Electric drill sub-frames McGRAW-EDISON CO 24 Sept 1971 [6 Oct 1970] 44660/71 Heading B3C [Also in Division H2] For a portable power tool, an electric motor and sub-frame assembly comprises two stamped metal plates 10, 12 in contiguous engagement throughout a substantial portion of their surfaces, -secured together by means, e.g. rivets 14, and each having complementary cut outs defining an opening 18 in which is mounted an electric switch having a shaft 26 mountedinbearings 24 mounted in complementary struck out portions 22 in the plates adjacent opposite sides of the motor receiving opening 18 on different opposite sides of which are located two brush holder spaces each defined by a struck out portion 50 of one plate 10 opposite notch 54 in the other plate 12 in which spaces means, e.g. screws 80 secure respective brush holders. The latter are doubly insulated, comprising outer and inner inserts 56, 60 of differing insulating materials, and house spring biased brushes 36 engaging a commutator 34 and which are electrically contacted by connectors 68 receiving leads 70 gripped by notches 84 in a brush holder projection 82. The plates 10, 12 have strengthening flanges 16, and openings 20 and struck out portions 46 receiving the gears and spherical bearings of a transmission 40 driving an output shaft 42 to which may be connected either a chuck or a rotary to reciprocating motion converting mechanism, e.g. if the tool is a hedge trimmer. An impeller 28 draws air through the tool housing (not shown), and the stator 30 is mounted in the sub-frame by an insulating mounting means 48.