Abstract: In a self-reversing tapping attachment an improved coolant system includes at least one fluid flow orifice at the end of a fluid flow conduit contained in a drive spindle member and further includes a fluid contact member for generating force to prevent interference with the drive spindle member prior to tapping a hole. Provision is further made for self-correction of any tendency for back pressure of fluid flow to interfere with motion of the drive spindle member by provision for covering the fluid flow orifice during motion under back pressure, thereby reducing such pressure. A collector chamber and exit orifice for expulsion to ambient of coolant fluid prevent invasion of the inner mechanism by coolant under back pressure.

Abstract: A screw thread cutting apparatus (tapping attachment) which is provided with a clutching apparatus within the attachment, having the capability of de-clutching the drive from the driver in the event of excessive torque. The clutching apparatus involves a clutching member or members carried by the driver and a clutching member or members carried by the driven part, and a displaceable clutching member which can produce a clutching or de-clutching action between the other members. The clutching apparatus can be built into an adapter for holding a tap provided with quick change capability. The clutching apparatus can also be built directly into the driver.

Abstract: The invention is an apparatus for producing clutching and de-clutching particularly adaptable for use in a tapping attachment for threading holes. The clutching apparatus includes clutching members driven by the driver or driving machine and clutching members carried by the driven part. An intermediate member is provided which provides for clutching engagement and de-clutching between the members on the driving part and the members on the driven part. The clutching apparatus has the capability of producing de-clutching in response to excessive torque applied to the apparatus, and also, it has the capability of producing de-clutching in response to the tap having reached a predetermined depth and the hole being tapped. The apparatus can be built into a tapping attachment or into a tap holding adapter having the capability of quick change release, and also, the mechanism can be built directly into the driving apparatus.

Abstract: Clutching device particularly adapted for use in tapping attachments. The clutch is of the type having axial aligned driving and driven elements. The invention is illustrated in a reversible tapping attachment. In a preferred form the driving element is in the form of a sleeve having axial splines. The driven element has axial grooves. A ball retainer with angularly spaced balls provides for drive between the drive element and the driven element, the balls being engageable with the axial splines and with the axial grooves in the driven element. The improvement resides in that the axial grooves are not of the same width as the diameter of the balls but are of a width greater than the diameter of the balls, the width being preferably twice the diameter of the balls. Improved operation is realized in clutching and declutching and in the transfer through a neutral zone from direct drive to reverse drive. In the preferred embodiment the tapping attachment is of the free-axial float type.

Abstract: Thread-milling machine incorporating one driving and one driven unit (14, 10), between which are provided means for the transfer of torque (22) permitting mutual axial displacement of the two units. Between the two units are mounted spring elements, one of which (36) is tensioned when the units are moved away from one another and the other (58, 60) being tensioned when the two units are moved in the opposite direction to this. The elements (34, 50) mounted between the spring elements are so arranged as to balance the freedom of movement of the units towards or away from each other from an initial position determined by the tension of the springs. The elements (34, 50) mounted between the spring elements are provided with pressure devices (88; 96; 108; 116) so designed as to increase the resistance to axial displacement of the units towards one another regardless of the preset positions of the units (14, 10).