Drill, tap, and other object detector

Claim 2

A drill rotation detector comprising: a plurality of sensor means for scanning the fluted surfaces of a plurality of drills and producing respective pulse trains at the rates the flutes are scanned; indicator means having first and second conditions; and circuit means responsive to the pulses collectively from the plurality of sensor means to maintain the indicator means in one condition and responsive to the absence of pulses from any one of said sensor means to place the indicator means in the other of said conditions, said circuit means comprising a plurality of coincidence gates, each having one input connected to receive pulses from a selected sensor means and another input connected to the output of a preceding gate.

Claim 3

A detector as dEfined in claim 1 wherein each sensor means comprises a U-shaped magnetic core disposed along side a drill path, means for inducing flux in the core, and means for responding to the changes in flux in the core to produce the pulses.

Claim 4

A detector as defined in claim 2 wherein the legs of the U-shaped core are spaced by a gap which is small as compared to the diameter of a drill in the path.

Claim 5

A detector as defined in claim 1 wherein the circuit means comprises an SCR having a gate electrode connected to receive the pulses from the sensor means.

Claim 6

A detector as defined in claim 4 including a full wave rectifier connected in circuit with the SCR to permit the application of AC power thereto.

Claim 7

A detector as defined in claim 1 wherein the indicator means comprises a lamp.

Claim 8

A sensor as defined in claim 1 wherein the means for inducing flux is a permanent magnet.

Claim 9

A detector as defined in claim 4 including relay means for disabling an external circuit in response to the failure of the SCR to conduct.

Claim 10

Apparatus for continuously detecting and indicating the rotation of a homogeneous, fluted, elongated and axially displaceable tool, such as a drill, comprising: tool guide means having an aperture through which the tool passes during the axial displacement thereof, sensor means including a discontinuous magnetic core carried by the guide means and having pole pieces defining a gap, both of said pole pieces being disposed adjacent, but radially spaced from one side of the tool when in the tool guide aperture, means for inducing a flux in the core and in the gap adjacent the tool guide aperture whereby rotation of the flutes of the tool past the gap produce a time-varying amplitude in the flux in the core, winding means on the core for producing electrical pulses in response to the time-varying amplitude of the flux flow whereby the rate of occurrence of said pulses is related to the rate of rotation of said tool, indicator means having first and second conditions, and circuit means connecting the winding means and the indicator means and being responsive to the pulses for maintaining the indicator means in one of the conditions so long as pulses from said probe are received at a predetermined rate but placing the indicator means in the other of said conditions when pulses are not received at the predetermined rate.

Claim 11

Apparatus for continuously detecting and indicating the rotation of a homogeneous, fluted, elongated and axially displaceable tool, such as a drill, comprising: tool guide means having an aperture through which the tool passes during the axial displacement thereof, sensor means including a discontinuous magnetic core carried by the guide means and having pole pieces defining a gap, both of said pole pieces being disposed adjacent, but radially spaced from one side of the tool when in the tool guide aperture, means for inducing a flux in the core and in the gap adjacent the tool guide aperture whereby rotation of the flutes of the tool past the gap produce a time-varying amplitude in the flux in the core, winding means on the core for producing electrical pulses in response to the time-varying amplitude of the flux flow whereby the rate of occurrence of said pulses is related to the rate of rotation of said tool, indicator means having first and second conditions, and circuit means connecting the winding means and the indicator means and being responsive to the pulses for maintaining the indicator means in one of the conditions so long as pulses from said probe are received at a predetermined rate but placing the indicator means in the other of said conditions when pulses are not received at the predetermined rate.

Claim 12

Apparatus as defined in claim 9 wherein the gap is small as compared to the diameter of the tool in the tool guide means.

Claim 13

Apparatus as defined in claim 10 wherein the sensor means comprises a U-shaped bracket connected to the tool guide means and carrying the core, said bracket being radially adjustable relative to the tool guide means to accommodate tools of varying radial dimension.

Claim 14

Apparatus as defined in claim 9 wherein said means for inducing is a permanent magnet carried by the sensor means adjacent said core.

Claim 15

Apparatus as defined in claim 9 wherein said sensor means comprises an expansible collar adapted to fit over and be supported by a drill guide bushing, said core being carried by said collar.