Adjustable clutch

Claim 2

A power tool comprising a housing, motor means within said housing and including output rotary shaft means, rotary tool means supported by said housing, torque-transmitting clutch means within said housing and interconnecting said output shaft means and said tool means, compression spring means outside said housing and operatively engageable with said clutch means to bias the latter into torque-transmitting relationship, sleeve means encompassing said spring means and longitudinally adjustable on said housing to vary the force of said spring means on said clutch means, and manually releasable means normally engageable with said sleeve means and preventing longitudinal movement thereof relative to said housing.

Claim 3

A tool as defined in claim 1 wherein said sleeve means is threaded on said housing.

Claim 4

A tool as defined in claim 2 wherein said manually releasable means is slidably longitudinally on said housing and nonrotatable relative thereto, said manually releasable means adapted to interlock with said sleeve means to prevent rotation thereof.

Claim 5

A tool as defined in claim 2 wherein said manually releasable means includes a manually grippable ring axially slidable on said housing, and spring means normally biasing said ring axially into locking engagement with said sleeve means.

Claim 6

A tool as defined in claim 2 wherein said manually releasably means includes a relatively small keylike member axially slidable on said housing, spring means normally biasing said keylike member into locking engagement with axially extending slot means in said sleeve means.

Claim 7

A tool as defined in claim 1 which includes thrust-bearing means between said compression spring and said clutch means.

Claim 8

A tool as defined in claim 6 wherein said clutch means comprises radially disposed confronting members coupled to said output shaft means and said rotary tool means, one of said members having a plurality of arcuately spaced openings each having a ball disposed therein, the other of said members having arcuately spaced pockets adapted to receive respective ones of said balls, said thrust-bearing means including unrestrained annular means engaging said balls on the side opposite said other member.

Claim 9

A tool as defined in claim 1 which includes normally disengaged positive clutch means between said torque-transmitting clutch means and said tool means, said positive clutch means being engageable when said tool means is pressed against a workpiece.

Claim 10

A portable power tool for driving screws and the like comprising a housing, a motor driven rotary shaft in said housing, tool spindle means, clutch means interconnecting said rotary shaft and tool spindle means for torque transmission therebetween, said clutch means comprising a plurality of arcuately spaced balls rotatably carried by one and receivable in recesses formed in the other of said rotary shaft and tool spindle means, pressure means engageable with said balls, resilient means normally biasing said pressure means in one direction to hold said balls in said recesses, whereby to transmit torque directly between said rotary shaft and said tool spindle means below a predetermined torque level, said resilient means being yieldable in response to said predetermined torque level in said clutch means to allow said balls to move out of said recesses in the other of said rotary shaft and tool spindle means and roll along surface means between said recesses, whereby said rotary shaft can turn relative to said spindle means, and thrust bearing means between said resilient means and said pressure means, whereby said pressure means is free to turn and enhances true rolling action of said balls between said recesses, whereby substantially no torque above said predetermined level is transmitted from said shaft to said spindle means.

Claim 11

A portable power tool for driving screws and the like comprising a housing, a motor driven rotary shaft in said housing, tool spindle means, clutch means interconnecting said rotary shaft and tool spindle means for torque transmission therebetween, said clutch means comprising a plurality of arcuately spaced balls rotatably carried by one and receivable in recesses formed in the other of said rotary shaft and tool spindle means, pressure means engageable with said balls, resilient means normally biasing said pressure means in one direction to hold said balls in said recesses, whereby to transmit torque directly between said rotary shaft and said tool spindle means below a predetermined torque level, said resilient means being yieldable in response to said predetermined torque level in said clutch means to allow said balls to move out of said recesses in the other of said rotary shaft and tool spindle means and roll along surface means between said recesses, whereby said rotary shaft can turn relative to said spindle means, and thrust bearing means between said resilient means and said pressure means, whereby said pressure means is free to turn and enhances true rolling action of said balls between said recesses, whereby substantially no torque above said predetermined level is transmitted from said shaft to said spindle means.

Claim 12

A tool as defined in claim 9 wherein said pressure means includes an annular member bearing against said balls on the side thereof opposite said recesses, said annular member being unrestrained against turning movement about a central axis thereof, said balls being disposed around a circle coaxial with said annular member.

Claim 13

A tool as defined in claim 10 wherein said recesses, said balls, and said annular member are axially disposed.

Claim 14

A portable power tool comprising a housing, a motor driven rotary shaft in said housing, tool spindle means, clutch means interconnecting said rotary shaft and tool spindle means, said clutch means comprising a plurality of arcuately spaced balls rotatably carried by one and receivable in recesses formed in the other of said rotary shaft and tool spindle means, pressure means internally of said housing and engageable with said balls, resilient means externally of said housing, means partially inside and partially outside said housing operatively interconnecting said resilient means and said pressure means, whereby said resilient means normally biases said pressure means in one direction to hold said balls in said recesses, whereby to transmit torque between said rotary shaft and said tool spindle means, said resilient means being yieldable in response to a predetermined torque in said clutch means to allow said balls to move out of said recesses in the other of said rotary shaft and tool spindle means and roll along surface means between said recesses, whereby said rotary shaft can turn relative to said spindle means, and thrust-bearing means between said resilient means and said pressure means, whereby said pressure means is free to turn and facilitates rolling action of said balls between said recesses.

Claim 15

A portable power tool comprising a housing, a motor driven rotary shaft in said housing, tool spindle means, clutch means interconnecting said rotary shaft and tool spindle means, said clutch means comprising a plurality of arcuately spaced balls rotatably carried by one and receivable in recesses formed in the other of said rotary shaft and tool spindle means, pressure means internally of said housing and engageable with said balls, resilient means externally of said housing, means partially inside and partially outside said housing operatively interconnecting said resilient means and said pressure means, whereby said resilient means normally biases said pressure means in one direction to hold said balls in said recesses, whereby to transmit torque between said rotary shaft and said tool spindle means, said resilient means being yieldable in response to a predetermined torque in said clutch means to allow said balls to move out of said recesses in the other of said rotary shaft and tool spindle means and roll along surface means between said recesses, whereby said rotary shaft can turn relative to said spindle means, and thrust-bearing means between said resilient means and said pressure means, whereby said pressure means is free to turn and facilitates rolling action of said balls between said recesses.

Claim 16

A tool as defined in claim 12 wherein said interconnecting means includes a plate disposed inside said housing and having radial projections extending outside said housing.

Claim 17

A tool as defined in claim 12 wherein said interconnecting means is nonrotatably associated with said housing.