CONTROLLED FORCE DRIVE AND RELATED METHOD OF USE

1 . A controlled force drive element for use with a rotational power tool comprising:

a primary drive body including a chuck connector adapted to join with a chuck of a rotational power tool;

a secondary drive body reciprocally joined with the primary drive body;

a biasing element adapted to urge the secondary body to an extended mode, the biasing element compressible under a force to allow the secondary body to retract to a retracted mode while advancing a fastener with the drive element;

a tool bit joined with the secondary drive body including a drive head distal from the primary drive body;

wherein the biasing element is compressible under the force so that as the biasing element compresses, the drive head moves toward the primary drive body and the secondary drive body retracts to the retracted mode, and so that as the biasing element decompresses, the drive head moves away from the primary body and the secondary drive body extends to the extended mode;

wherein the primary drive body, secondary drive body, tool bit and drive head form a spring-loaded drive line that exerts a preselected force on a fastener engaged by the drive head as the drive head rotates and advances the fastener.

2 . The controlled force drive element of claim 1 comprising a force indicating element, the force indicating element outputting at least one of audible and visual output to inform a user of at least one of a force applied to the fastener by the controlled force drive element and the preselected force, wherein the preselected force is suitable for advancing the fastener into a work piece at a desired advancement rate that avoids damage to the work piece.

3 . The controlled force drive element of claim 1 ,

wherein the secondary drive body defines a socket,

wherein the tool bit includes a shaft,

wherein the shaft is disposed in the socket.

4 . The controlled force drive element of claim 3 wherein the socket includes a retainer, the retainer engaging the tool bit to retain the tool bit in the socket and associated with the secondary drive body.

5 . The controlled force drive element of claim 4 wherein the socket is distal from the biasing element and the primary drive body.

6 . The controlled force drive element of claim 1 ,

wherein the primary drive body includes a housing,

wherein the secondary drive element includes a connector body,

wherein the connector body is slidably received within the housing.

7 . The controlled force drive element of claim 6 , comprising:

a pin joined with at least one of the housing and the connector body, and

a slot defined by the other of the at least one of the housing and the connector body,

wherein the pin is registered in the slot so as to constrain the movement of the connector body relative to the housing when the secondary drive body retracts to the retracted mode.

8 . A controlled force drive element for use with a rotational power tool comprising:

a primary drive body including a chuck connector adapted to join with a chuck of a rotational power tool, the primary drive body including a longitudinal axis;

a tool bit reciprocally joined with the primary drive body, the tool bit including a shaft having a first end and a drive head at a second, opposing end of the shaft, the drive head including a drive feature adapted to remain registered with a fastener upon rotation of the tool bit so as to rotate the fastener with the tool bit;

a biasing element joined with at least one of the primary drive body and the tool bit, the biasing element configured to compress under a force as the drive head engages the fastener to allow the tool bit and the drive head to retract toward the primary drive body,

wherein the primary drive body, tool bit and drive head form a spring-loaded drive line that exerts a preselected force on a fastener engaged by the drive head as the drive head rotates and advances the fastener.

9 . The controlled force drive element of claim 8 comprising a connector body defining a socket, the connector body slidably joined with the primary drive body, wherein the tool bit is registered within the socket without the tool bit extending into the primary drive body when the connector body is in an extended mode.

10 . The controlled force drive element of claim 8 ,

wherein the biasing element includes a first magnet joined with the tool bit and a second magnet joined with the primary drive body, the first magnet and second magnet repelling one another with a magnetic force so as to urge the tool bit away from the primary body and into an extended mode,

wherein when drive head engages the fastener and the force becomes greater than the magnetic force, the tool bit retracts toward the primary body.

11 . The controlled force drive element of claim 10 ,

wherein the primary drive body includes a housing,

wherein the first and second magnets are located within the housing,

wherein the second magnet is located adjacent the first end of the tool bit.

12 . The controlled force drive element of claim 8 ,

wherein the primary drive body defines a bore and includes an exterior,

wherein the shaft of the tool bit is slidably registered in the bore,

wherein the tool bit includes a biasing element engagement member,

wherein the biasing element includes a coil spring,

wherein the coil spring is disposed around the exterior of the housing,

wherein the coil spring engages the biasing element engagement member to urge the drive head away from the primary drive body.

13 . The controlled force drive element of claim 8 ,

wherein the biasing element is a coil spring,

wherein the coil spring is disposed around an exterior of the primary drive body,

wherein the coil spring is interposed between the primary drive body and the tool bit.

14 . The controlled force drive element of claim 8 wherein the tool bit retracts toward the primary drive body at least ½ inch when the biasing element compresses under the force as the drive head engages the fastener.

15 . The controlled force drive element of claim 8 ,

wherein the primary drive body is in the form of a housing,

wherein the tool bit is rigidly and fixedly joined with the housing,

wherein the chuck connector is engaged with the biasing element.

16 . The controlled force drive element of claim 8 comprising a connector body joined with the housing, the connector body defining a socket, the first end of the tool bit disposed in the socket.

17 . The controlled force drive element of claim 8 comprising;

a connector body, the connector body defining a socket, the connector body forward of the primary drive body along the longitudinal axis, the first end of the tool bit seated in the socket, and

a force indicating element outputting at least one of audible and visual output to inform a user of at least one of the force applied as the drive head engages the fastener and the preselected force, wherein the preselected force is suitable for advancing the fastener into a work piece at a desired advancement rate that avoids damage to the work piece.

18 . The controlled force drive element of claim 16 wherein the force indicating element includes a pin that moves in response to the tool bit moving toward the primary drive body, the pin registered in a slot defined by the primary drive body.

19 . A controlled force drive element for use with a rotational power tool comprising:

a primary drive body including a chuck connector adapted to join with a chuck of a rotational power tool, the primary drive body including a longitudinal axis, the primary drive body forming a housing having and exterior and defining an internal bore, the housing defining a slot that extends to the exterior;

a secondary drive body including a connector body, the connector body slidably joined with the primary drive body and registered at least partially within the internal bore, the connector body defining a socket, the socket including a retainer;

a tool bit including a shaft having a first end and a drive head at a second, opposing end of the shaft, the drive head including a drive feature adapted to remain registered with a fastener upon rotation of the tool bit so as to rotate the fastener with the tool bit, the first end of the shaft the tool bit registered within the socket, without the tool bit extending into the primary drive body when the connector body is in an extended mode, the retainer of the socket engaging the tool bit to retain the tool bit in the socket and associated with the connector body, the tool bit and connector body being generally immovable relative to one another when joined;

a biasing element adapted to urge the secondary body to an extended mode, the biasing element compressible under a force to allow the secondary body to retract to a retracted mode while advancing a fastener with the drive element;

a pin joined with at least one of the connector body and the tool bit, the pin registered in the slot defined by the housing and slidable within the slot when the secondary body retracts to a retracted mode;

wherein the biasing element is compressible under the force so that as the biasing element compresses, the drive head of the tool bit moves toward the primary drive body and the secondary drive body retracts to the retracted mode, and so that as the biasing element decompresses, the drive head moves away from the primary body and the secondary drive body extends to the extended mode;

wherein the housing includes a primary force indicating element on the exterior adjacent the slot,

wherein the pin aligns with the primary force indicating element when the secondary drive body retracts to the retracted mode under the force, thereby indicating to a user that a preselected force suitable for advancing the fastener has been achieved,

wherein the primary drive body, secondary drive body, tool bit and drive head form a spring-loaded drive line that exerts the preselected force on the fastener engaged by the drive head as the drive head rotates and advances the fastener.

20 . The controlled force drive element of claim 19 ,

wherein the biasing element is a coil spring disposed in the internal bore of the housing,

wherein the coil spring directly engages the connector body, but not the tool bit.