Portable pneumatic power tool

Claim 2

In a portable pneumatic power tool, particularly in a screw driver, a combination of a pneumatic motor having a rotary output device; a normally closed valve for connecting said motor with a source of compressed gas so that the latter is started in response to opening of said valve; a rotary tool spindle coaxial with and movable axially toward and away from said output device; a coupling having complementary first and second coupling portions respectively rotatable on said spindle and secured to said output device, said first coupling portion being movable into engagement with said second coupling portion in response to axial movement of said spindle toward said output device; a clutch including a first clutch section rotatable with and axially of said spindle, a second clutch section provided on said first coupling portion, and means for biasing said first clutch section into torque-receiving engagement with said second clutch section; a valve actuating member movable to and from an inopErative position in which said valve is closed; displacing means mounted in said spindle and arranged to move said actuating member from said inoperative position to thereby start said motor in response to movement of said spindle towards said output device; and anchoring means provided in said first clutch section to receive at least a portion of said displacing means in response to shifting of said first clutch section against the opposition of said biasing means when said spindle offers a predetermined resistance to rotation with said output device whereby said displacing means allows said actuating member to reassume said inoperative position with attendant stoppage of said motor, said displacing means being arranged to hold said first clutch section against movement into torque receiving engagement with said second clutch section when said displacing means extends into said anchoring means.

Claim 3

The combination of claim 1, further comprising resilient means for biasing said tool spindle away from said output device.

Claim 4

The combination of claim 1, further comprising means for adjusting the resistance of said biasing means to shifting of said first clutch section.

Claim 5

The combination of claim 1, wherein said actuating member is a rod and said valve comprises means for biasing said rod to said inoperative position, said rod being received in aligned axial bores provided therefor in said output device and said tool spindle.

Claim 6

The combination of claim 4, wherein said anchoring means includes at least one recess provided in said first clutch section and arranged to receive a portion of said displacing means under the action of said last mentioned biasing means and said rod in response to shifting of said first clutch section against the opposition of said first mentioned biasing means.

Claim 7

The combination of claim 1, wherein said first clutch section comprises a sleeve shiftable axially of and arranged to rotate with said tool spindle, a flange provided on said sleeve, and at least one torque receiving element arranged to receive torque from said second clutch section and to thus rotate said flange when said tool spindle offers less than said predetermined resistance to rotation with said output device.

Claim 8

The combination of claim 6, wherein said sleeve is a sliding fit on said tool spindle, said anchoring means including at least one radial bore provided in said sleeve and said flange having a socket for said torque receiving element.

Claim 9

The combination of claim 1, wherein said second clutch section comprises at least one spherical torque transmitting element received in a conical socket of said first coupling portion.

Claim 10

The combination of claim 1, wherein said valve comprises a valve member and resilient means for biasing said valve member to a sealing position in which said valve is closed, said actuating member comprising a rod reciprocable in axial bores provided therefor in said tool spindle and said output device, said rod having a first end face abutting against said valve member and a second end face normally abutting against said displacing means under the action of said resilient means.

Claim 11

The combination of claim 9, wherein said output device comprises a rotary motor shaft and a coaxial second shaft driven by said motor shaft and arranged to rotate said second coupling portion.

Claim 12

In a portable pneumatic power tool, particularly in a screw driver, the combination of a pneumatic motor having a rotary output device; a normally closed valve for connecting said motor with a source of compressed gas so that the latter is started in response to opening of said valve; a rotary tool spindle coaxial with and movable axially toward and away from said output device; a coupling having complementary first and second coupling portions respectively rotatable on said spindle and secured to said output device, said first coupling portion being movable into engagement with said second coupling portion in response to axial moVement of said spindle toward said output device; a clutch including a first clutch section rotatable with and shiftable axially of said spindle and comprising at least one pin-shaped element, a second clutch section provided on said first coupling portion, and means for biasing said first clutch section into torque receiving engagement with said second clutch section, said spindle comprising a sleeve arranged between said first and said second clutch sections and having at least one axially parallel bore in which said pin-shaped element is axially movably received and arranged to receive torque from said second clutch section when said motor drives said first coupling portion and said tool spindle offers less than a predetermined resistance to rotation with said output device; a valve actuating member movable to and from an inoperative position in which said valve is closed; displacing means mounted in said spindle and arranged to move said actuating member from said inoperative position to thereby start said motor in response to movement of said spindle towards said output device; and anchoring means provided in said first clutch section to receive at least a portion of the displacing means in response to shifting of said first clutch section against the opposition of said biasing means when said spindle offers said predetermined resistance to rotation with said output device whereby said displacing means allows said actuating member to reassume said operative position with attendant stoppage of said motor.

Claim 13

In a portable pneumatic power tool, particularly in a screw driver, the combination of a pneumatic motor having a rotary output device; a normally closed valve for connecting said motor with a source of compressed gas so that the latter is started in response to opening of said valve; a rotary tool spindle coaxial with and movable axially toward and away from said output device; a coupling having complementary first and second coupling portions respectively rotatable on said spindle and secured to said output device, said first coupling portion being movable into engagement with said second coupling portion in response to axial moVement of said spindle toward said output device; a clutch including a first clutch section rotatable with and shiftable axially of said spindle and comprising at least one pin-shaped element, a second clutch section provided on said first coupling portion, and means for biasing said first clutch section into torque receiving engagement with said second clutch section, said spindle comprising a sleeve arranged between said first and said second clutch sections and having at least one axially parallel bore in which said pin-shaped element is axially movably received and arranged to receive torque from said second clutch section when said motor drives said first coupling portion and said tool spindle offers less than a predetermined resistance to rotation with said output device; a valve actuating member movable to and from an inoperative position in which said valve is closed; displacing means mounted in said spindle and arranged to move said actuating member from said inoperative position to thereby start said motor in response to movement of said spindle towards said output device; and anchoring means provided in said first clutch section to receive at least a portion of the displacing means in response to shifting of said first clutch section against the opposition of said biasing means when said spindle offers said predetermined resistance to rotation with said output device whereby said displacing means allows said actuating member to reassume said operative position with attendant stoppage of said motor.

Claim 14

The combination of claim 11, wherein said first clutch section further comprises a flange adjacent to said sleeve and having a socket for a portion of said pin-shaped element, said biasing means comprising resilient means arranged to bias said flange toward said sleeve.

Claim 15

The combination of claim 12, wherein the outer diameter of said flange equals the outer diameter of said sleeve, said flange surrounding said tool spindel and being movable axially thereof under and against the action of said resilient means.

Claim 16

The combination of claim 12, wherein said pin-shaped element comprises a pointed first end portion receiving motion from said second clutch section and a conical second end portion received in said socket of said flange.

Claim 17

In a portable pneumatic power tool, particularly in a screw driver, the combination of a pneumatic motor having a rotary output device; a normally closed valve for connecting said motor with a source of compressed gas so that the latter is started in response to opening of said valve; a rotary tool spindle coaxial with and movably axially toward and away from said output device; a coupling having complementary first and second coupling portions respectively rotatable on said spindle and secured to said output device, said first coupling portion being movable into engagement with said second coupling portion in response to axial movement of said spindle towards said output device; a clutch including a first clutch section rotatable with and shiftable axially of said spindle, a second clutch section provided on said first coupling portion, and means for biasing said first clutch section into torque receiving engagement with said second clutch section; a valve actuating member movable to and from an inoperative position in which said valve is closed; displacing means mounted in said spindle and arranged to move said actuating member from said inoperative position to thereby start said motor in response to movement of said spindle towards said output device, said displacing means comprising two discrete members located in a bore provided in and extending transversely of the axis of said tool spindle; and anchoring means provided in said first clutch section and comprising two discrete recesses provided in said first clutch section and each arranged to receive a portion of one of said displacing members in response to shifting of said first clutch section against the opposition of said biasing means when said spindle offers a predeteRmined resistance to rotation with said output device, whereby said displacing means allows said actuating member to reassume said inoperative position with attendant stoppage of said motor.

Claim 18

In a portable pneumatic power tool, particularly in a screw driver, the combination of a pneumatic motor having a rotary output device; a normally closed valve for connecting said motor with a source of compressed gas so that the latter is started in response to opening of said valve; a rotary tool spindle coaxial with and movably axially toward and away from said output device; a coupling having complementary first and second coupling portions respectively rotatable on said spindle and secured to said output device, said first coupling portion being movable into engagement with said second coupling portion in response to axial movement of said spindle towards said output device; a clutch including a first clutch section rotatable with and shiftable axially of said spindle, a second clutch section provided on said first coupling portion, and means for biasing said first clutch section into torque receiving engagement with said second clutch section; a valve actuating member movable to and from an inoperative position in which said valve is closed; displacing means mounted in said spindle and arranged to move said actuating member from said inoperative position to thereby start said motor in response to movement of said spindle towards said output device, said displacing means comprising two discrete members located in a bore provided in and extending transversely of the axis of said tool spindle; and anchoring means provided in said first clutch section and comprising two discrete recesses provided in said first clutch section and each arranged to receive a portion of one of said displacing members in response to shifting of said first clutch section against the opposition of said biasing means when said spindle offers a predeteRmined resistance to rotation with said output device, whereby said displacing means allows said actuating member to reassume said inoperative position with attendant stoppage of said motor.

Claim 19

The combination of claim 15, wherein each of said displacing members is a sphere and said actuating member is a rod which is reciprocable in an axial bore of said tool spindle.