Ratchet spanner for use on car engine spark plugs - has head with hole for tommy bar and receiving drive bit and houses ratchet wheel and pawl

摘要

The ratchet spanner for removing spark-plugs utilises a balanced two-handed applied couple, and comprises a rotatable head (A) which receives a transmission bit (B). The head (A) houses the ratchet wheel and pawl and is traversed at the top by a diametric "tommy" bar (21). The "tommy" bar projects on both sides for couple application. The bit projects from the head in the form of a tubular spigot (2a) which receives the haunches of a range of box spanners. The bit is fixed in the head by a tangential cotter pin (14) engaging a circumferential groove (13) and is thus fixed axially yet free to rotate. The liaison between the bit (2-5) and the ratchet wheel (9) is provided by a square section bit zone (7) engaging a matching wheel hole.