US3551743A

US3551743A - Static eliminator

Info

Publication number: US3551743A
Application number: US707163A
Authority: US
Inventors: Donald H Koepke; Lewis F Jennings
Original assignee: Varco Inc
Current assignee: Varco Inc
Priority date: 1968-02-21
Filing date: 1968-02-21
Publication date: 1970-12-29
Anticipated expiration: 1987-12-29

Description

United States Patent [1113,551,743

[72] Inventors Donald H. Koepke 2,087,915 7/1937 Kimball ..i 317/2 Elgin; 3,162,787 12/1964 Hanscom et a1. 317/2 Lewis F. Jennings, McHenry, 111. 940,431 I 1/1909 Chapman 317/2 [211 App]. No. 707,163 3,133,193 5/1964 Guillotte et a1. 250/49,5(62) [22] Filed Feb. 21, 1968 3,137,806 6/1964 Schweriner 317/2 [45] Patented Dec. 29, 1970 3,346,253 10/1967 Paschke 250/49.5(60) [73] Assignee Varco Incorporated 3,396,308 8/1968 Whitmore 317/4 I corporation oflllinois FOREIGN PATENTS 887,507 1/1962 Great Britain 317/2 [54] STATIC ELIMINATOR 4 Claims, 5 Drawing Figs.

[52] [1.8. CI 317/2, 250/495 [51 Int. Cl. H05x 3/04 [50] Field ofSearch 317/2, 2.1, 2.3, 3, 4, 2; 226/94; 250/49.560, 49.5-61, 495-62 [5 6] References Cited UNITED STATES PATENTS 1,680,310 8/1928 Wehrle 317/2 Primary Examiner-J. D. Miller Assistant Examiner-C. L. Yates Attorney-Hofgren, Wegner, Allen, Stellman & M cCord ABSTRACT: A generator-type static electricity neutralizer, preferably for use in business machines wherein webs of material, such as paper, are fed therethrough characterized in that the several emitter points of the neutralizer have a smooth shape which terminates in a sharp point, thereby eliminating undesired secondary emitting points.

STATIC ELIMINATOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a generator-type static electricity eliminator structure.

2. Description of the Prior Art The prior art of the type of structure disclosed and claimed ierein is amply represented by the Schutz U.S. Pat. No. 3,283,209, owned by the assignee of this invention and the prior art cited therein, including the following U.S. Pat. Nos. 940,431, to Chapman; 2,392,808, to Chapman; 3,137,806, to

Schweriner; 3,162,787, to Hanscom; 3,174,748. to Roberts.

Generally speaking, the prior art construction includes pointlike discharge elements in conductive contact with an element which is connected to a source of high voltage and negligible current. The discharge elements may be within a casing having a connection to ground. The prior art further teaches that a charge of high voltage and low amperage may be used to send current through the discharge elements to create an atmosphere of free ions which neutralize the charge of static electricity in webs or strips of material fed past the discharge elements.

While the prior art structures have been satisfactory for performing the function of neutralizing static electricity, they have possessed the shortcomings of being relatively expensive, and being so constructed as to be possessed of several areas of possible secondary emittance. In particular, in many of the prior art references the discharge element or emitter point is joined to the conductive element at a juncture resulting in a relatively sharp corner. Such corners or square edges result in areas of secondary emittance. Also the discharge point itself may have relatively square ends, resulting in more areas of secondary emittance.

Furthermore, in many known static eliminator structures the discharge point is surrounded with a ground conductor by placing the point in the center of a hole cut into the surface of a tube. In assembly, it has been found extremely difficult to center the point with sufficient accuracy so that the field will be concentrated towards the nearest ground path. This distorts field pattern and also requires that voltage be lowered to avoid shorting out on a shorter than planned path.

Finally, many of the structures shown in the prior art are relatively large for the desired area in which they are intended to be used. I

Thus, a need has arisen to provide an improved static eliminator of the generator type which is extremely compact, for use in office business machinery, is inexpensive to produce and is extremely efiicient in that all areas of secondary emittance are eliminated.

SUMMARY OF THE INVENTION This invention is directed, in brief, to the provision of an improved static eliminator of the generator type wherein the emitter points thereof are so constructed and arranged so as to eliminate any areas of secondary emittance. The best mode currently contemplated for carrying out the invention is the provision of a thin metallic member, preferably copper, clad with gold, having one edge serrated with smooth, generally semicircular cutout areas forming a continuous edge of smoothly formed teeth. The metallic member is secured to a thin, elongate insulated backing member on the other side of which a thin, elongate metallic ground member is secured. The assembly may be positioned within an insulating casing of limited dimension.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view, partially broken away in a section, of the static eliminator assembly of this invention;

FIG. 2 is a side elevational view of the static eliminator bar subassembly;

FIG. 3 is a side elevational view taken from the opposite side of FIG. 2;

FIG. 4 is a sectional view taken generally along the lines 4-4 of FIG. 1, and;

FIG. 5 is a fragmentary enlarged sectional view of a modified form of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT therebetween, forming a generally U-shaped structure having a hollow interior 22 and an open end 24 between the free ends of the sides 20a and 20b. A static bar receiving notch 26 is formed in the interior of the top 200 and the sidewalls 20a and 20b have mutually inwardly facing opposed ribs 28a and 28b.

The bar 12 includes a thin, elongate base 30 of suitable insulating material, preferably plastic, such as a phenolic or fiber glass. On face 30b there is mounted by suitable means, such as an adhesive or the like, a thin, flat, elongate metallic emitter element 32, preferably made of copper having a thin coating of gold. On face 30a of base 30 there is also secured by suitable means, such as adhesive, a thin, elongate metallic ground element 34 which also is preferably formed copper or the like.

The ground member 34 has two generally linear parallel sides 34a and 34b which terminate in semicircular rounded ends 340 and 34d. An opening 36 is formed through the base 30 and through the end 340 of ground element 34 for connecting ground wire 18 to ground element 34 by suitable means, such as soldering.

' Emitter element 32 has a straight side 40 and opposite round ends 42 and 44. Rounded end 44 has an opening 46 therethrough which also extends through the insulating bar 30, this opening being on the end opposite of the opening 36 which extends through end 34c of ground element 34. Opening 46 is for the reception of a portion of lead wire 16 which is, by means such as soldering or secured to the emitter bar 32 the like.

The edge of the emitter element 32 opposite straight edge 40 is provided with a plurality of sharp emitter points 48. The space between each of the emitter points 48 is a smooth semicircular are 50.

By way of example only, and not by way of limitation, the following are representative dimensions of one embodiment, it being understood that such dimensions will differ with respect to the intended use and installation of the static eliminator. By way of example, in one such embodiment the dimension between the

holes

46 and 36 is 15%inches, with the height of the insulating base 30 from top to bottom being five-eighths inch and the height of the ground element being one-quarter inch. The arcs 50 are formed on a one-half inch radius so that the several points 48 are 1 inch apart. In the same example, the point 48 seen at the right of FIG. 2 is 1 inch from the centerline of opening 36 and the point 48 at the other end is 1 inch from the centerline of pole 46.

In the modified embodiment shown in FIG. 5, the area of the emitter element 32 adjacent point 48 has one flat face 480 which may lie adjacent the insulating base 30, and an undercut inner face 48b so that the point 48 is sharply pointed in two planes.

As can be seen from FIG. 4, the bar 12 may be mounted within the insulating cover I4 with the top of the assembly snugly received in the notch 26 in the interior of cover 14 so that the inwardly directed ribs 28a and 28b abut the opposite faces of the bar 32 thereby positioning the discharge points 48 at the open end 24 of the housing 14 and generally medially spaced between the sides 20a and 20b thereof.

In operation, it is intended that the static eliminator of this assembly may be used in business machinery of the type through which webs or strips of paper or similar sheet material is fed at high speeds, such as a machine sold by the assignee of this invention and referred to as a Uarco 1747 Burster." As the web of paper is fed through the machine, static electricity is created. Electrical current of low amperage, but of approximately 5,000 volts or any other suitable voltage is applied to line 16, creating free ions adjacent the points 48 to neutralize static electricity created by the moving web of paper. Because there are no sharp or square corners other than the discharge points 48 themselves, there will be almost no stray emittage. The device may be manufactured to great accuracy in that the two

openings

36 and 46 are used as registration points for the

elements

32 and 34 and the top and bottom of the insulator base 30 may be easily sheared to obtain close dimensional accuracy. The preferred embodiment is very compact in that the overall thickness of the assembly including the housing is only three-eighths. inch and the dimension from top to bottom of the assembly including the insulating housing is three-quarters inch. The bar assembly, itself, is only five-eighths inch from top to bottom, and l6% inches in length, although the length can be varied depending upon the width of the path of paper feed across which it is intended that this assembly is to span.

The manufacture and assembly of this structure is extremely simple in that the

strips

32 and 34 to opposite faces of the base 30, and with merely two soldering operations at opposite ends of the base to connect the electrical and ground leads thereto.

The insertion of the bar assembly 12 within the insulating housing 14 may be by a simple frictional force fit. Thus, this invention provides an improved static eliminator assembly of the generator type which is easily and economically manufactured and assembled, and is compact and highly efficient in operation.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as some modifications may be obvious to those skilled in the art.

We claim:

1. A static eliminator comprising: an elongate base of insulating material; a conductive discharge element on said base, said conductive element having an edge andhaving means for connection to a source of electrical energy, a conductive ground element on said base with meansfor connection to ground; said discharge element having a plurality of discharge points spaced from the edge along the length of the edge thereof; each discharge point being joined to said conductive element by a substantially smooth, generally arcuate surface; and a generally U-shaped insulating housing having an open end and having surfaces on the interior thereof for embracing and holding the eliminator with the discharge points facing out of the open end of the housing.

2. A static eliminator comprising: a thin elongate base of insulating material having two opposite faces; a thin conductive ground element on one face of the base with means for connection to ground; a thin conductive discharge element on the opposite face of the base having an edge and having means for connection to a source of electrical energy, the conductive discharge element having a plurality of recesses in the edge forming a plurality of discharge points therealong; and a generally U-shaped insulating housing having an open end and having surfaces of the interior thereof for embracing and holding the eliminator with the discharge points facing out of the open end of the housing.

3. A thin static eliminator comprising: a thin elongate base of insulating material having two opposite faces; a thin conductive ground element on one face of the base with means for connection to ground; and a thin conductive discharge element on the opposite face of the base having an edge and including means for connection to a source of electrical energy, a plurality of recesses in the edge forming a plurality of discharge points therealong, the opposite ends of the conductive discharge element and the juncture of the discharge points therewith being smoothly rounded.

4. A static eliminator comprising: a thin elongate base of insulating material having two opposite faces; a thin conductive ground element on one face of the base with means for connection to ground; a thin conductive discharge element on the opposite face of the base having an edge and including means for connection to a source of electrical energy and a plurality of recesses in the edge forming a plurality of discharge points therealong, said ground and conductive elements being laterally offset relative to each other; and lead wire openings formed in opposite ends of the insulating base and through the conductive element at one end and the ground element at the other end.

*gg g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3,551,743 Dated December 29, 1970 Inventor) Donald H. Koepke and Lewis F. Jennings It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Page 1 of the patent, in the designation of the Assignee, "Varco Incorporated" should be --Uarco Incorporated.

Signed and sealed this 27th day of April 1971 (SEAL) Attest:

EDWARD M.FLETGHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents