Power drilling machine with resistance triggered retraction

Claim 2

A drilling machine which comprises a spindle, a housing, means for rotatably mounting the spindle in the housing, means for mounting the housing for movement with the spindle in spindle advancing and retracting directions, a lead screw, means for rotatably mounting the lead screw for movement parallel to the direction of housing movement, means for connecting the lead screw to the housing in driving relation, resilient means resisting movement of the lead screw in a direction opposite to that of housing and spindle feed movement, means for turning the lead screw to advance the housing and the spindle, rapid transverse means for rapidly advancing and retracting the housing and the spindle, the means for turning the lead screw including motor driven clutch means and means for releasing the clutch means when the rapid traverse means advances and retracts the housing and the spindle, the lead screw being free to rotate during driving by the rapid traverse means, switch means, switch operating means connected to the lead screw and arranged to actuate the switch when the lead screw advances a predetermined distance against the resilient means, and means operated by the switch means for causing the rapid traverse means to retract the housing and the spindle.

Claim 3

A drilling machine as in claim 1 wherein the rapid traverse means for rapidly advancing and retracting the housing and the spindle includes a hydraulic cylinder and means connected to the housing and driven by the cylinder for driving the housing and the spindle in rapid traverse.

Claim 4

A drilling machine as in claim 1 wherein the means for rotatably mounting the lead screw includes a barring cup, bearings in the bearing cup rotatably supporting an end portion of the lead screw, and means for supporting the bearing cup for movement lengthwise of the axis of the lead screw, an elongated switch operating trip rod is attached to the bearing cup to move therewith, an annular spring housing surrounds a portion of the trip rod with another portion of the trip rod extending outwardly of the spring housing, a compression spring is mounted in the spring housing engaging the bearing cup to urge the bearing cup in spindle feed direction, and the outwardly extending portion of the trip rod engages the switch operating means to actuate the switch when the lead screw is advanced the predetermined distance.

Claim 5

A drilling machine as in claim 1 wherein there is means for rotating the spindle including a spring urged member which shifts position when there is a predetermined resistance to turning of the spindle, second switch means, second switch operating means engageable by said member when said member shifts position to actuate the second switch means, and means operated by the second switch means for retracting the housing and the spindle.

Claim 6

A drilling machine which comprises a spindle, a housing, means for rotatably mounting the spindle in the housing, means for mounting the housing for movement with the spindle in spindle advancing and retracting directions, a lead screw, means for rotatably mounting the lead screw for movement parallel to the direction of housing movement, means for connecting the lead screw to the housing in driving relation, resilient means resisting movement of the lead screw in a direction opposite to that of housing and spindle feed movement, means for turning the lead screw to advance the housing and the spindle, switch means, switch operating means connected to the lead screw and arranged to actuate the switch when the lead screw advances a predetermined distance against the resilient means, means operated by the switch means for retracTing the housing and the spindle, rod means attached to the housing to move with the housing, first and second dog means mounted on the rod means, first and second limit switches having actuators engageable with the first and second dog means, the actuator of the first limit switch being engageable with the first dog means when the housing is fully retracted, the actuator of the second limit switch being engageable with the second dog means when the housing is fully extended, a third limit switch having a switch actuator, a third dog means mounted on the rod means, the actuator of the third limit switch being engageable with the third dog means when the housing is at a position for shifting from rapid advance to a feed stroke, the rapid traverse means advancing the housing until the third limit switch is actuated, means controlled by the third limit switch for engaging the clutch means when the third limit switch is actuated to cause feed advance of the housing, means actuated by the second limit switch for releasing the clutch means and for causing rapid retraction of the housing when the second limit switch is actuated, and means controlled by the first limit switch for arresting rapid retraction of the housing when the first limit switch is actuated.

Claim 7

A drilling machine which comprises a spindle, a housing, means for rotatably mounting the spindle in the housing, means for mounting the housing for movement with the spindle in spindle advancing and retracting directions, a lead screw, means for rotatably mounting the lead screw for movement parallel to the direction of housing movement, means for connecting the lead screw to the housing in driving relation, resilient means resisting movement of the lead screw in a direction opposite to that of housing and spindle feed movement, means for turning the lead screw to advance the housing and the spindle, switch means, switch operating means connected to the lead screw and arranged to actuate the switch when the lead screw advances a predetermined distance against the resilient means, means operated by the switch means for retracTing the housing and the spindle, rod means attached to the housing to move with the housing, first and second dog means mounted on the rod means, first and second limit switches having actuators engageable with the first and second dog means, the actuator of the first limit switch being engageable with the first dog means when the housing is fully retracted, the actuator of the second limit switch being engageable with the second dog means when the housing is fully extended, a third limit switch having a switch actuator, a third dog means mounted on the rod means, the actuator of the third limit switch being engageable with the third dog means when the housing is at a position for shifting from rapid advance to a feed stroke, the rapid traverse means advancing the housing until the third limit switch is actuated, means controlled by the third limit switch for engaging the clutch means when the third limit switch is actuated to cause feed advance of the housing, means actuated by the second limit switch for releasing the clutch means and for causing rapid retraction of the housing when the second limit switch is actuated, and means controlled by the first limit switch for arresting rapid retraction of the housing when the first limit switch is actuated.

Claim 8

A drilling machine as in claim 5 wherein the third dog means is slidably mounted on the rod means, stop means is provided for arresting the third dog means when the third limit switch has been actuated so that the rod means moves to position the third dog means at a new position on the rod means, the third dog means remaining in the new position when the housing is retracted after actuation of the lead screw actuated switch means, the housing being advanced to the position at which it was when the lead screw actuated switch means was actuated upon re-advance until the third dog means in its new position again actuates the third limit switch to return the machine to feed advance.

Claim 9

A drilling machine as in in claim 6 wherein there is dog resetting means engageable with the third dog means during retraction of the housing after actuation of the second limit switch which resets the third dog means at its original position on the rod means.