Abstract: A hammer mechanism (200,200') for a power tool comprises a housing (203), a chuck spindle (201) journalled for rotation in the housing and having axial freedom of movement in the housing, a rotary ratchet (204) fixed on the spindle, the ratchet having teeth (207) facing a rear end of the housing, a fixed ratchet (205) rotationally fixed in the housing but having axial freedom of movement in the housing, the fixed ratchet surrounding the spindle and having teeth (207) facing the teeth of the rotary ratchet, and a spring (213) between the fixed ratchet and housing resiliently biasing the fixed ratchet towards the rotary ratchet.A first cam (208,209) between the fixed and rotary ratchets has two positions. In a first position, the ratchets can engage one another, whereby reciprocal motion is imparted on the spindle on rotation thereof. In a second position the ratchets are prevented from inter-engagement.A second cam (224) between the fixed ratchet and housing have two positions.

Abstract: A power tool has an application mechanism (300) for connection to the output of an epicyclic gearbox provided with a torque control ring. The mechanism has a body (310) journalling a chuck spindle (302). Outside the body is a clutch control arrangement comprising balls (334,336) pressed against the torque control ring by individual springs (330) controlled by a control ring (322) threaded on the body. The mechanism includes a hammer arrangement having rotary and fixed ratchet plates (378,376) and cam ring (308) operable to engage and separate the plates by a lever (360) which projects between the springs (330).

Abstract: A chuck spindle device (300) has the following basic components:--a body (310), a bearing (316) mounting a chuck spindle (302) and an end cap (312) through which the spindle projects for connection to a gearbox. An annular space is defined in the body to receive a hammer mechanism in the form of rotary ratchet (378), fixed ratchet (376) and cam ring (308) to press them together. The body has a slot to accept a control knob (360) of the cam ring. The body is threaded (317) to receive a clutch mechanism in the form of control ring (322) and multiple springs (330) pressing balls (334,336) against a torque control ring of the gear box.