Cutting by use of rotating axially moving tool – With means to apply transient – fluent medium to work or product – Including nozzle
Patent
1993-01-29
1994-07-26
Howell, Daniel W.
Cutting by use of rotating axially moving tool
With means to apply transient, fluent medium to work or product
Including nozzle
408 67, 408 95, B23B 4700
Patent
active
053323416
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a pressure foot of a printed circuit board drilling apparatus and, more particularly, to a pressure foot of a printed circuit board drilling apparatus for improving the cooling efficiency of a drill bit.
BACKGROUND ART
As a pressure foot of a printed circuit board drilling apparatus for drilling printed circuit boards, for instance, pressure feet disclosed in Japanese Patent Unexamined Publication No. 63-300807, Japanese Patent Unexamined Publication No 3-3713 (corresponding to U.S. Pat. No. 5024562), and so forth have been proposed.
These pressure feet are designed such that compressed gas is ejected toward a drill bit from a groove formed in a lower end portion of the pressure foot, and that the drill bit is cooled by the compressed gas.
Increasing the machining speed and decreasing the frequency of replacement of the drill bit are expected for enhancing the productivity. Improving the quality of drilled holes is expected for responding to an increase in accuracy of equipments in which printed circuit boards are used, and suppressing generation of offensive odor caused by burning of printed circuit boards is expected for improving the operation environment.
They are subject matters which can be solved by increasing the cooling efficiency of the drill bit. In the prior art, however, cooling of the drill bit is effected by heat conduction through the compressed gas injected into the pressure foot, and consequently, it is impossible to expect the cooling efficiency of the drill bit to be largely enhanced.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a pressure foot of a printed circuit board drilling apparatus which can improve the cooling efficiency of a drill bit considerably and can solve the above-described subject matters.
A first embodiment of a pressure foot of a printed circuit board drilling apparatus according to the present invention, which is supported on a spindle of the printed circuit board drilling apparatus slidably in the axial direction, and which includes a pressing face which presses a printed circuit board at the time of drilling operation, a discharge port formed in a side wall so as to discharge chips produced by drilling operation, the discharge port being connected to a suction device, and a compressed air supply conduit formed in a side wall so as to eject the compressed air toward a drill bit of the printed circuit board drilling apparatus, is characterized in that a cooling fluid supply device is connected to the compressed air supply conduit.
A cooling fluid atomizing nozzle can be employed as the cooling fluid supply device. The cooling fluid atomizing nozzle comprises an outer pipe with a spout, an inner pipe which is inserted in the outer pipe so as to form an annular compressed air conduit between the inner surface of the outer pipe and the inner pipe, and which includes a cooling fluid conduit formed therein and an opening portion opened toward the spout, and a needle member which is inserted in the inner pipe movably in the axial direction, and which controls an opening area of the opening portion of the inner pipe.
Preferably, the supply conduit should extend in a tangential direction of the drill bit.
A second embodiment of a pressure foot of a printed circuit board drilling apparatus according to the invention, which is supported on a spindle of the printed circuit board drilling apparatus slidably in the axial direction, and which includes a pressing face which presses a printed circuit board at the time of drilling operation, and a discharge port formed in a side wall so as to discharge chips produced by drilling operation, the discharge port being connected to a suction device, is characterized in that a fluid supply conduit for ejecting a cooling fluid toward a drill bit of the printed circuit board drilling apparatus is formed in the side wall, and that at least one groove extending in a tangential direction of the drill bit is formed in the pressing face so as to allow the air
REFERENCES:
patent: 2650557 (1953-09-01), Hauser
patent: 3398609 (1968-08-01), Schott
patent: 3478843 (1969-11-01), Eckardt
patent: 3577808 (1971-05-01), Visser
patent: 4037982 (1977-07-01), Clement
patent: 4915550 (1990-04-01), Arai et al.
patent: 4917547 (1990-04-01), Frederickson et al.
patent: 5213454 (1993-05-01), Givler et al.
Arai Kunio
Hamada Kazunori
Kanaya Yasuhiko
Hitachi Seiko Ltd.
Howell Daniel W.
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