Work holders – With fluid means – Vacuum-type holding means
Reexamination Certificate
1999-04-01
2001-02-06
Watson, Robert C. (Department: 3723)
Work holders
With fluid means
Vacuum-type holding means
Reexamination Certificate
active
06182956
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to vacuum tables. More specifically, the invention is a vacuum table for securing a removably attached matting.
2. Description of Related Art
Vacuum tables have been used in the engraving and manufacturing industries for many years. Often, the table is damaged during engraving, milling, drilling, or other applications. This necessitates either costly repair or repurchase of a vacuum table, and adds to machine down time. A vacuum table with a removable and replaceable mat would therefore be beneficial.
Understandably, vacuum tables and related devices have been the subject of previous patents. U.S. Pat. No. 5,374,021, issued to Kleinman on Dec. 20, 1994, discloses a vacuum holder particularly useful as a vacuum table. The device includes a vacuum chamber divided into a plurality of sub-chambers which ultimately lead to a plurality of suction opening which extend through an outer holding surface for applying suction to a workpiece. U.S. Pat. No. 4,301,999, issued to Higgins et al. on Nov. 24, 1981, discloses a vacuum hold-down table for working with sheet metal. The table includes a plurality of foam layers united to form a laminated core having a plurality of apertures such that a vacuum may be applied through these apertures for holding sheet metal in place. U.S. Pat. No. 4,205,835, issued to Gerber on Jun. 3, 1980, discloses a bristle bed for a vacuum table. The bristle board includes aperture in the base that provide passageways for airflow through a mat in communication with a vacuum source.
Document scanners and copiers have benefitted from the use of vacuum tables for holding papers in place. U.S. Pat. No. 5,486,932, issued to Leonard on Jan. 23, 1996, and its European counterpart, EPO patent document 0,603,430 published Jun. 29, 1994, disclose a document scanner and vacuum table therefor. The table uses an array of openings to exert suction pressure generated by a vacuum on an object above to hold the object in place.
Vacuum tables have also been developed for other tasks, such as decal welding and laser engraving. U.S. Pat. No. 5,695,600, issued to Goin on Dec. 9, 1997, and U.S. Pat. No. 5,504,301, issued to Eveland on Apr. 2, 1996, are respective examples thereof.
Other devices using the power of vacuum have also been the subject of previous patents. Among them are: U.S. Pat. No. 5,685,513 (vacuum-suction attachment pad) issued to Tsukushi on Nov. 11, 1997; EPO document 0,265,648, published on May 4, 1988; and EPO document 0,505,668, published on Sep. 30, 1992.
Although many vacuum table designs exist, a system using a replaceable mat in a vacuum table which retains workpieces with a suction-cup like grip would be both useful and beneficial for various applications.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
A vacuum table according to the present invention includes a vacuum plate, a mat, and a vacuum system. The vacuum plate forms a base for the unit and is provided with an aperture through which air is pulled by a vacuum pump. The mat rests on the vacuum plate and is sealed therewith by a gasket. A base sheet of the mat is provided with a plurality of perforations which are connected on the underside of the base sheet by a network of channels. The channels allow for even pull of air from under the mat through to the vacuum pump. A rubber sheet is affixed to the upper surface of the base sheet. A plurality of small holes are defined by the rubber sheet corresponding to the perforation of the base sheet. A vacuum pull beneath the mat forces the rubber sheet to cave in at each perforation of the base sheet, thereby creating a plurality of suction-cup like indentations on the upper surface which ultimately hold a workpiece in place.
Accordingly, it is a principal object of the invention to secure a workpiece to a work surface via vacuum pressure.
It is another object of the invention to secure a work piece to a work surface via vacuum pressure exerted below a mat causing the mat perform in a suction-cup like manner.
It is a further object of the invention to facilitate ease of repair of a vacuum table.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
REFERENCES:
patent: 3598006 (1971-08-01), Gerber et al.
patent: 4205835 (1980-06-01), Gerber
patent: 4301999 (1981-11-01), Higgins et al.
patent: 4656906 (1987-04-01), Mozieka et al.
patent: 5374021 (1994-12-01), Kleinman
patent: 5486932 (1996-01-01), Leonard
patent: 5504301 (1996-04-01), Eveland
patent: 5685513 (1997-11-01), Tsukushi
patent: 5695600 (1997-12-01), Goin
patent: 0265648 (1988-05-01), None
patent: 0505668 (1992-09-01), None
patent: 0603430 (1994-06-01), None
Litman Richard C.
Watson Robert C.
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