Cutting by use of rotating axially moving tool – Processes – Bit detachable
Reexamination Certificate
1999-06-18
2001-02-27
Wellington, A. L. (Department: 3722)
Cutting by use of rotating axially moving tool
Processes
Bit detachable
C408S124000, C408S130000, C408S137000
Reexamination Certificate
active
06193447
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to positive feed tools, such as right angle positive feed drills, and more particularly, to a method and apparatus for retracting a spindle of the drill by actuating a valve.
2. Description of the Related Art
Positive feed tools, such as positive feed drills are conventionally known for drilling holes in workpieces formed of substances, such as steel, aluminum, titanium, and composites. Positive feed drills include a drill feed mechanism that feeds a drill bit into the workpiece.
During drilling with positive feed drills, cutting chips are generated when the drill bit penetrates through the workpiece. These chips may affect the final dimension of the drilled hole if they are not removed during the drilling process. Additionally, the cutting chips occasionally cease the drill bit, which may damage the spindle, gears, bearings, or other components of the drill.
One technique for removing chips during drilling is called “peck drilling.” Peck drilling refers to a drilling technique whereby the rotating drill bit is advanced and then occasionally or periodically retracted to remove the cutting chips from the drilled hole and the flutes of the drill bit.
Some positive feed drills include a mechanism by which an operator of the positive feed drill can cause the spindle of the drill to retract.
For example, one conventional positive feed drill includes a retract lever. The spindle of the drill may be manually retracted by the operator physically pulling the retract lever up, in a direction away from the tool. With this conventional drill the spindle will continue to retract until the retract lever is physically pushed back down again, in a direction toward the tool. When the retract lever of this tool is pulled up, the differential feed gear of the tool is mechanically disengaged from the differential drive gear of the tool. Additionally, the differential feed gear is prevented from rotating when the retract lever is pulled up. Because the differential feed gear is prevented from rotating, the spindle will retract. However, with this technique of retracting the spindle, the retract lever must be manually forced down after the desired amount of retracting has occurred. This is problematic because the retract lever is necessarily located near the head of the drill, where the spindle and drill bit are rotating. Thus, many operators of such drills are wary of repeatedly moving the retract lever to peck drill.
Another conventional right angle positive drill also includes a manual retract lever near the spindle of the drill, which must be lifted upward to retract the spindle. When the spindle fully retracts, the motor of the tool is shut down. With this conventional drill, the spindle cannot be advanced after the retract lever has been pulled, unless the tool is completely shut off either manually or by permitting the spindle to fully retract, which will automatically shut off the motor of the tool. Only after the spindle has fully retracted and the motor has been shut down can an operator cause the spindle to once again advance toward the workpiece. Thus, it is very difficult for an operator of this conventional drill to remove cutting chips by peck drilling.
Thus, it is apparent that conventional positive feed drills are not well suited for peck drilling, and thus occasionally suffer from the problems associated with cutting chips, namely ceased spindles and galled holes. The above-described constraints and problems associated with conventional positive feed tools has created a need for a positive feed tool that may be used to peck drill more easily than conventional positive feed drills.
SUMMARY OF THE INVENTION
Generally speaking, the present invention provides a positive feed tool that may be used to peck drill a workpiece.
According to one aspect of the present invention, a positive feed tool includes a positive feed tool having a threaded spindle, and a spindle drive gear coupled to the spindle such that the spindle and the spindle drive gear rotate together. A spindle feed gear is threaded on the spindle. A differential drive gear is engaged with the spindle drive gear. A differential feed gear is engaged with the spindle feed gear. At least one of the differential feed gear and the differential drive gear is moveable from a first position to a second position. The differential feed gear is coupled to the differential drive gear when the one of the differential feed gear and the differential drive gear is located at the first position such that the differential feed gear and the differential drive gear rotate together. The differential feed gear is not coupled to the differential drive gear when the at least one of the differential feed gear and the differential drive gear is located at the second position. The tool also includes a retract valve having a member manually movable from a first location to a second location. The member defines a seal when located at the first location. The retract valve is configured to automatically return the member to the first location after the member is manually moved from the first location to the second location and after the valve has been released. The retract valve causes the at least one of the differential feed gear and the differential drive gear to move to the second position from the first position when the member is at the second location. The retract valve causes the at least one of the differential feed gear and the differential drive gear to move to the first position from the second position when the member is at the first location.
In accordance with a further aspect of the present invention, the retract valve is located toward the rear of the positive feed tool.
According to another aspect of the present invention, a positive feed tool includes a spindle, a motor, and a drive train rotatably connecting the motor and the spindle. The tool includes a manually openable valve, a device for automatically closing the valve after the valve has been manually opened and released, and a device for causing the spindle to retract when the valve is manually opened, and a device for causing said spindle to advance when said valve is automatically closed.
In accordance with another aspect of the present invention, a method in a positive feed tool includes: retracting an advancing spindle of the tool by manually actuating the valve of the tool, and then advancing the retracting spindle after the valve is released.
A further aspect of the present invention pertains to a positive feed tool having a rotatable spindle adapted to undergo advancing movement and retracting movement. The tool further includes a motor, and a drive train rotatably connecting the motor and the spindle. The drive train causes the spindle to undergo the advancing movement and causes the spindle to under go the retracting movement. A manually actuatable fluid valve is operable in a first mode that causes the spindle to switch from the advancing movement to the retracting movement and is operable in a second mode that causes the spindle to switch from the retracting movement to the advancing movement.
Other objects, advantages and features associated with the present invention will become readily apparent to those skilled in the art from the following detailed description. As will be realized, the invention is capable of other and different embodiments, and its several details are capable of modification in various obvious aspects, all without departing from the invention. Accordingly, the drawings and the description are to be regarded as illustrative in nature, and not limitative.
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Jensen Sam C.
Thames Bruce A.
Carter Monica S.
Coats & Bennett PLLC
Cooper Technologies Company
Wellington A. L.
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