US 2006/0185481 A1Published application

Electric driver

AssigneeNitto Kohki Co., Ltd.

InventorsToshio Mikiya, Takayuki Okamoto, Tameyoshi Oshima, Yasuo Kazama

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Abstract

A power screwdriver (10) includes a bit holder (14) bored to receive the shaft of a screwdriver bit (12) and adapted to securely hold the screwdriver bit (12) in place, and a housing (18) having a through cavity (16). The bit holder (14) is inserted into the through cavity (16) so that the bit holder (14) is rotatable about and movable along the axis of the bit holder. This arrangement securely holds the screwdriver bit and thus, minimize rattling of the screwdriver bit during rotation.

Claims10

Dependent claims

A power screwdriver comprising:

a bit holder having a distal end, a proximal end and an axis, said bit holder being adapted to receive a bit shank to hold a screwdriver bit in place;
a housing having a distal end, a proximal end and an exterior, said housing including a through cavity axially extending from said distal end to said proximal end of said housing and shaped to receive said bit holder so that said bit holder is rotatable about said axis and axially slidable within said through cavity, and an annular bore defined between said through cavity and said exterior of said housing, said annular bore being open to said distal end of said housing and extending from said distal end toward said proximal end of said housing;
a cam axially spaced from said proximal end of said bit holder and including a cam surface extending at right angles to said axis and oriented toward said proximal end of said housing, said cam surface having a circular cam path extending about said axis;
a drive shaft connected to said cam to cause said cam to rotate about said axis;
a clutch element disposed between said bit holder and said cam and engaged with said circular cam path;
a compression spring disposed within said annular bore and providing a compressive force;
a thrust member engaged with said compression spring and extending out of said housing through said proximal end of said housing, said thrust member being operable to transmit said compressive force to said clutch element and urge said clutch element against said cam surface;
and
a compressive force regulating member releasably mounted to said distal end of said housing and engaged with one end of said compression spring, said compressive force regulating member being axially displaced to regulate said compressive force of said compression spring,
said cam path including a raised land axially projecting from said cam surface toward said proximal end of said bit holder, said clutch element being engaged with said raised land to thereby transmit rotational torque to said bit holder when said cam is caused to rotate, said clutch element being forced to ride over said raised land to thereby release said rotational torque when said rotational torque exceeds a predetermined value.

7 more elements

Dependencies are inferred from the claim text.

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Abstract

A power screwdriver comprising:

a bit holder having a distal end, a proximal end and an axis, said bit holder being adapted to receive a bit shank to hold a screwdriver bit in place;
a housing having a distal end, a proximal end and an exterior, said housing including a through cavity axially extending from said distal end to said proximal end of said housing and shaped to receive said bit holder so that said bit holder is rotatable about said axis and axially slidable within said through cavity, and an annular bore defined between said through cavity and said exterior of said housing, said annular bore being open to said distal end of said housing and extending from said distal end toward said proximal end of said housing;
a cam axially spaced from said proximal end of said bit holder and including a cam surface extending at right angles to said axis and oriented toward said proximal end of said housing, said cam surface having a circular cam path extending about said axis;
a drive shaft connected to said cam to cause said cam to rotate about said axis;
a clutch element disposed between said bit holder and said cam and engaged with said circular cam path;
a compression spring disposed within said annular bore and providing a compressive force;
a thrust member engaged with said compression spring and extending out of said housing through said proximal end of said housing, said thrust member being operable to transmit said compressive force to said clutch element and urge said clutch element against said cam surface;
and
a compressive force regulating member releasably mounted to said distal end of said housing and engaged with one end of said compression spring, said compressive force regulating member being axially displaced to regulate said compressive force of said compression spring,
said cam path including a raised land axially projecting from said cam surface toward said proximal end of said bit holder, said clutch element being engaged with said raised land to thereby transmit rotational torque to said bit holder when said cam is caused to rotate, said clutch element being forced to ride over said raised land to thereby release said rotational torque when said rotational torque exceeds a predetermined value.

7 more elements