Cutting by use of rotating axially moving tool – Machine including plural tools – Coaxial tools
Reexamination Certificate
1999-08-30
2001-07-03
Howell, Daniel W. (Department: 3722)
Cutting by use of rotating axially moving tool
Machine including plural tools
Coaxial tools
C408S053000, C408S089000, C408S103000
Reexamination Certificate
active
06254318
ABSTRACT:
BACKGROUND OF THE INVENTION
Sica U.S. patent application Ser. No. 09/187,950, filed Nov. 6, 1998, and entitled “All-weather Flourescent Lamp With a Protective Assembly” (hereinafter “Sica”), discloses a protective assembly for a standard fluorescent lamp of the type having an elongated glass tube and a metal terminal cap at each end of the glass tube, each cap having a flange portion adjacent the glass tube. The assembly includes a protective tube that is preformed from a semi-rigid non-frangible polymeric transparent or translucent material that is stabilized against ultraviolet radiation and is received over the glass tube with its inner surface substantially uniformly spaced apart from the outer surface of the glass tube to form an air space for insulation of the lamp. The protective tube is substantially coextensive with the full diameter portion of the glass tube lengthwise of the lamp and is securely fastened to the flange portions of the lamp. The protective tube protects the lamp from impacts, thus reducing the possibility of the lamp being accidentally broken. In the event that the lamp does break, the protective tube remains intact and secured to the end caps of the lamp so as to form an enclosure that keeps broken glass fragments, phosphor powders and mercury from escaping to the environment.
The all-weather characteristic of the lamp of Sica is obtained by forming numerous small vent holes in portions of the protective tube proximate to the end caps. The vent holes are of a size such that fragments of glass from a broken lamp tube cannot pass through them. The number of vent holes is such that the air gap between the glass tube of the lamp and the protective tube is vented to permit the lamp to operate without substantial reduction in light output and without substantial discoloration of the protective tube in the range of ambient temperatures of from about 50° F. to −30° F. Sica is incorporated into the present specification for all purposes.
For proper operation of the lamp of Sica—i.e., substantially undiminished light output over the aforementioned broad range from moderately cool to very cold temperatures and prevention of discoloration and other effects of over-heating of the lamp near the upper end of the range—it is important that the vent holes be formed within a close tolerance. Variations in the diameters and lengths of the holes may significantly alter the ventilating properties, which can lead to either overcooling and loss of light output at low temperatures or overheating at temperatures near the high end of the desired operating range.
SUMMARY OF THE INVENTION
An object of the present invention is to provide apparatus for producing the vent holes in the protective tube with high precision, thus to ensure proper functioning of the vent holes in all protective tubes produced over long production runs. Another object is to provide apparatus for forming the vent holes that is reliable, relatively inexpensive, easy to use, and efficient.
The foregoing and other objects are attained, according to the present invention, by apparatus for making numerous spaced-apart radially extending holes in a tube that includes a rotary index table that is adapted to be rotated intermittently through predetermined index angles of rotation about a table axis and to dwell between each rotation. A mandrel affixed to the index table is adapted to be received telescopically within an end portion of the tube and hold the tube in a fixed position relative to the mandrel with the axis of the tube coaxial with the table axis. A pair of self-feed drilling units mounted on opposite sides of the mandrel have output shafts that are driven intermittently in reciprocating motion along axes lying in a common plane with the longitudinal axis of the tube, the axis of each output shaft being perpendicular to the longitudinal axis of the tube. Each output shaft carries a multiple-spindle head, each spindle of the multiple-spindle head receiving a drill bit.
The tube in which the holes are to be made is inserted over the mandrel. The drill units cycle and drill multiple longitudinally spaced-apart, radially extending holes in each side of the tube, the holes being diametrically opposite each other. During a dwell period of the drill units at the end of the drilling cycle, the index table rotates through a predetermined angle and stops. While the index table dwells, the drill units cycle again and drill another set of diametrically opposite holes in the tube. The indexing of the tube rotationally and the cycling of the drill units is repeated until the desired number of holes have been drilled in the tube. The apparatus provides holes of the same diameter with a high degree of precision and ensures that all of the holes lie radially with respect to the axis of the tube, which in turn means that the holes are all of the same length—equal to the wall thickness of the tube. Repeatability of the accuracy of the hole sizes is ensured over all production of the tubes, thereby fulfilling the requirement of consistent venting of the all-weather protected fluorescent lamps in which the tubes are used.
In preferred embodiments of the apparatus, the axes of the output shafts of the drilling units are aligned, the number of spindles of the multiple-spindle heads are equal, and the spacings of the spindles of the heads are the same. With that configuration the completed hole set in the tube has longitudinal sets of holes arranged in circumferential rows. Preferably, the machine is set up or controlled to index the tube rotationally through the same index angle, the angle being equal to 360 degrees divided by the number of holes in each circumferential row. The same index angle results in the spacing of the adjacent holes in each circumferential row being equal. For example, if each circumferential row is to have 20 holes, the index angle is set to 18 degrees.
In advantageous embodiments of the invention, the mandrel is adapted to hold the tube in a fixed position relative to the mandrel by means of one or more resilient O-rings that are received in ring-grooves in the mandrel and resiliently engage the inner surface of the tube with an interference fit and to position the tube longitudinally by means of a stop shoulder that is engaged by the end of the tube. The O-ring(s) permits the tube to be inserted over the mandrel relatively easily and securely holds the tube frictionally as it is rotated with the mandrel and index table.
For a better understanding of the invention, reference may be made to the following description of an exemplary embodiment, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 272857 (1883-02-01), Coffin
patent: 391345 (1888-10-01), Stites
patent: 1854053 (1932-04-01), Millspaugh
patent: 2135696 (1938-11-01), Baumhauer et al.
patent: 2363109 (1944-11-01), Keiffer
patent: 2581959 (1952-01-01), Koehler
patent: 2877670 (1959-03-01), Allen
patent: 3358167 (1967-12-01), Shanks
patent: 3453470 (1969-07-01), Hammer
patent: 3602759 (1971-08-01), Evans
patent: 3635570 (1972-01-01), DeGelleke et al.
patent: 3720826 (1973-03-01), Gilmore et al.
patent: 3808495 (1974-04-01), Win
patent: 3833312 (1974-09-01), Miles et al.
patent: 3955896 (1976-05-01), Davis
patent: 3957386 (1976-05-01), Lupke
patent: 4048537 (1977-09-01), Blaisdell et al.
patent: 4162134 (1979-07-01), Kitagawa
patent: 4268196 (1981-05-01), Harrow et al.
patent: 4426062 (1984-01-01), Kawamura et al.
patent: 4493595 (1985-01-01), Klein
patent: 4529342 (1985-07-01), Babel
patent: 4606686 (1986-08-01), Weaver
patent: 4674925 (1987-06-01), Thornton et al.
patent: 4728229 (1988-03-01), Memmel et al.
patent: 4916352 (1990-04-01), Haim et al.
patent: 4924368 (1990-05-01), Northrop et al.
patent: 5173637 (1992-12-01), Sica
patent: 5494134 (1996-02-01), McConkey
patent: 5536998 (1996-07-01), Sica
patent: 5621964 (1997-04-01), Susnjara et al.
patent: 5729085 (1998-03-01), Sica et al.
patent: 141097 (1895-02-01), None
patent: 4011 (1876-01-01), None
patent: 16241 (1964-10-01), None
patent: 2806 (1989-01-01), N
Baker & Botts L.L.P.
Howell Daniel W.
LandOfFree
Apparatus for making numerous holes in a tube does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for making numerous holes in a tube, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for making numerous holes in a tube will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2538759