Multi-speed power tool transmission with alternative ring gear configuration

A power tool comprising:

• a housing defining a handle and a body;
• a motor received in the body;
• a trigger mounted to the handle and coupled to the motor, the trigger being adapted to control operation of the motor in response to an input provided by an operator of the power tool by coupling the motor to a source of power;
• an output member;
• a multi-speed transmission coupling the motor and the output member;
• and
• a switch mechanism having a switch and an actuator, the switch being movable between a first switch position, a second switch position, and a third switch position, the actuator being non-rotatably but axially slidably disposed in the housing between a first actuator position, a second actuator position, and a third actuator position, the actuator being engaged to one or more members of the multi-speed transmission at each of the first, second and third actuator positions such that the multi-speed transmission operates in a corresponding one of a plurality of different overall speed reduction ratios;
• wherein the multi-speed transmission and the switch mechanism are configured such that:
• (a) the actuator will move with the switch when the switch is moved from the second switch position to the third switch position;
• (b) the switch can move relative to the actuator when the switch is moved from the third switch position to the second switch position or from the second switch position to the first switch position;
• and
• (c) the switch can move relative to the actuator when the switch is moved from the first switch position to the second switch position.

A power tool comprising:

• a housing defining a handle and a body;
• a motor received in the body;
• a trigger mounted to the handle and coupled to the motor, the trigger being adapted to control operation of the motor in response to an input provided by an operator of the power tool by coupling the motor to a source of power;
• an output member;
• a multi-speed transmission coupling the motor and the output member, the multi-speed transmission comprising a first stage and a second stage, the first stage comprising a first sun gear, a plurality of compound planet gears, a first ring gear and a second ring gear, the first sun gear being driven by the motor and meshingly engaged with the compound planet gears, each compound planet gear having a first planet gear portion, which is meshingly engaged to the first ring gear, and a second planet gear portion that is fixed to the first planet gear portion for rotation therewith and meshingly engaged to the second ring gear, the second stage comprising a third ring gear that is axially movable between an inactive position, in which the third ring gear is engaged with a rotary member of the multi-speed transmission such that the third ring gear and the rotary member co-rotate, and an active position in which the third ring gear is disengaged from the rotary member;
• and
• a speed selector comprising a switch, an actuator, a first biasing spring, a second biasing spring and a third biasing spring, the switch being movable between a first switch position, a second switch position, and a third switch position, the actuator being non-rotatably but axially slidably disposed in the housing between a first actuator position, a second actuator position, and a third actuator position, the actuator being engaged to one or more members of the multi-speed transmission at each of the first, second and third actuator positions such that the multi-speed transmission operates in a corresponding one of a plurality of different overall speed reduction ratios;
• wherein the first biasing spring biases the actuator toward the switch when the switch is in the second position and the actuator is disposed between the third and second actuator positions;
• wherein the first biasing spring biases the actuator toward the switch when the switch is in the first position and the actuator is disposed between the second and first actuator positions;
• wherein the second biasing spring biases the actuator biasing the actuator away from the switch when the switch is in the second switch position and the actuator is disposed between the first and second actuator positions;
• and
• wherein the third biasing spring biases the third ring gear toward the actuator when the switch is in the third switch position, the actuator is in the third actuator position and the actuator is not engaged to the third ring gear.

A power tool comprising:

• a housing defining a handle and a body;
• a motor received in the body;
• a trigger mounted to the handle and coupled to the motor, the trigger being adapted to control operation of the motor in response to an input provided by an operator of the power tool by coupling the motor to a source of power;
• an output member;
• and
• a transmission coupling the motor and the output member;
• wherein the power tool is characterized by at least one of the following:
• (a) the transmission includes a first planetary stage and a second planetary stage, wherein the first planetary stage includes a planet carrier and a plurality of planet gears, the planet carrier comprising a plurality of pins onto which the planet gears are journally mounted, wherein the second planetary stage comprises a sun gear having an outer diameter onto which a plurality of sun gear teeth are formed, wherein the pins of the planet carrier are mounted to the sun gear radially inward of the sun gear teeth and wherein no portion of the sun gear that transmits torque is bigger in diameter than the outside diameter of the sun gear as measured across the sun gear teeth;
• (b) the transmission includes a first planetary stage and a second planetary stage, wherein the first planetary stage comprises a compound planet gear having a first ring gear, a second ring gear, and a first planet gear portion, which is meshingly engaged to the first ring gear, and a second planet gear portion that is coupled for rotation with the first planet gear portion and meshingly engaged with the second ring gear, and wherein the second planetary stage comprises a third ring gear that is axially movable between a first position, in which the third ring gear is meshingly engaged with a rotating component of the transmission, and a second position in which the third ring gear is disengaged from the rotating component;
• (c) the transmission includes a planetary stage having compound planetary gears with a first portion that is engaged to a first ring gear and a second portion that is engaged to a second ring gear, wherein the compound planetary gears are not timed to another gear in the transmission;
• (d) the transmission includes a planetary stage having a ring gear, a planet carrier and a plurality of planet gears, the planetary gears being meshingly engaged with the ring gear and journally supported on pins of the planet carrier, wherein adjacent ones of the pins are spaced apart by an angular spacing and wherein two or more different angular spacings are employed to thereby space the planet gears unevenly about the ring gear;
• (e) the power tool comprises a mode change mechanism having a cam, a cam follower, a planet gear and a ring gear, wherein the cam is rotatably mounted in the housing, the cam follower is engaged to the cam and non-rotatably but axially slidably mounted in the housing, wherein the planet gear is meshingly engaged with the ring gear and teeth formed on the cam, wherein rotation of the ring gear generates corresponding rotation or the cam to cause axial translation of the cam follower in the housing, wherein the cam follower is employed to selectively lock-out a torque clutch, position an axially movable hammer ratchet into a zone where it may be engaged by a rotary hammer ratchet that is mounted on the output spindle, or both;
• (f) the power tool comprises a spindle lock comprising a bushing that is coupled to an output member of the transmission at a first interface and to the output spindle at a second interface, at least one of the first and second interfaces being defined by a female portion and a male portion that is received in the female portion, the female portion being comprising a plurality of first V-shaped sidewalls that have peaks that face radially inwardly, the male portion comprising a plurality of second V-shaped sidewalls that are engaged the first V-shaped sidewalls, each of the first V-shaped sidewalls being defined by a first interior angle, each of the second V-shaped sidewalls being defined by a second interior angle that is smaller than the first interior angle to rotationally couple the female portion and male portion in a manner that provides limited rotational movement there between;
• (g) the power tool further comprises a clutch, the clutch having a plurality of follower members and a clutch spring, the follower members being received between a clutch profile on a ring gear of the transmission and the clutch spring, the clutch spring biasing the follower members into engagement with the clutch profile, wherein the clutch spring is an annular wave spring having a non-linear spring rate and preferably, a non-linear spring rate in which a plot depicting a load exerted by the clutch spring as a function of clutch spring deflection has a distinct knee between a first portion, which is generally defined by a first spring rate, and a second portion that is generally defined by a second spring rate that is greater than the first spring rate;
• (h) the power tool further comprises a torque clutch and a clutch bypass member, the torque clutch comprising a clutch profile, which is coupled to a ring gear of the transmission, and a follower member that is biased into engagement with the clutch profile to resist rotation of the ring gear when a magnitude of the torque output from the power tool does not exceed a clutch torque, the clutch bypass member comprising a plurality of lugs that are non-rotatably but slidably engaged to the housing, the clutch bypass member being axially movable between a first position, in which lugs are axially separated from the ring gear, and a second position in which the lugs are received within the ring gear such that the lugs are positioned radially inwardly of the clutch profile;
• (l) the transmission includes a planetary stage having a ring gear, the ring gear being axially movable between a first position and a second position to cause a change in a speed ratio of the transmission, the power tool further comprising a spring that is mounted coaxially about the transmission to bias the ring gear into one of the first and second positions;
• and
• (j) the housing further comprises a gear case into which at least a portion of the transmission is received, and a plurality of frusto-conical features are formed onto the body and the gear case to align the two to a common rotary axis.