US2278538A - Insect screen - Google Patents

Description

April 7, 1942. w. DUBILIER 2,278,538

INSECT SCREEN Filed March 16, 1940 INVENTOR. William @uln'lier ATTORNEYS Patented Apr.f7, 1942 UNITED STATES PATENT OFFICE INSECT SCREEN William Dubilier, New York, N. Y. Application March 16, 1940, Serial No. 324,416

3, Claims.

charged for various purposes and especially to v screens arranged to destroy insects upon contact.

Heretofore in the construction of insect destroying electrically charged members it has been the practice to wind a pair of 'wires on a plurality of spaced insulating posts and then to place behind the wires some means of attracting the insects. The insects, when they contacted two adjacent wires received the charge of the current through them and thus were supposed to be electrocuted. I

In the construction of such insect destroying members means were sometimes utilized to preserve a permanent spacing of the wires, although in most instances the tension upon the conductive wires themselves was the sole means relied upon to prevent the short-circuiting thereof. The wires could not be effectively closely spaced since on any relaxation in tension on the wires or any stretching of the wires they would contact each other. Furthermore, the spacing means here utilized was necessarily, therefore, of such a cumbersome nature as to increase the space between the wires and to prevent the wires from acting effectively as an insect destroying means.

In accordance with my present invention I have woven a screen, the warp of which com-- prises strands of insulating material and the weft of which comprises conductive metallic wires. Owing to the fact that these warp and weft strands are woven in the same manner as is any other type of screen cloth, each of the weft wires is effectively prevented from at any time coming into contact with adjacent weft wires.

While in specific constructions I prefer that the weft constitute the conductive wires and the warp the insulating strands, it may be possible in specific types of construction to reverse this alignment and to make the conductive wires the warp strands.

For thepurpose of creating such an insulating screen mounting for the conductive wires I have found that a synthetic thermo-sensitive resinous material such as nylon or any other type of synthetic thermo sensitive material having insulating qualities may be utilized to form the insulat-- ing strands of the screen.

, Although many types of insulating strands may be utilized, I prefer to use Nylon for this purpose, but it should be understood that in the following description the term Nylon is used as a generic mm to indicate generally thermo-setting and 0a thermo-plastic resilient material, preferably in the form of single filament strands.-

By the use of Nylon for this purpose I may provide a screen, the insulating strands of which are crimped to effectively space each of the wires from the other. The crimps in each of the Nylon strands being resilient may yield to a deforming force, that is, should the strands be deformed or tensioned for any reason the crimps may be straightened out, but upon relaxation of such deformation and tension the crimps will be restored to their original position.

This specific type of crimping of the strands of Nylon itself is in accordance with the copending application of H. W. Thomas for Screen material and method of making same,'Serial No. 324,393 filed simultaneously herewith.

For purposes of the present invention the conductive wires may be crimped similarly if desired, although this is not essential.

The insecticidal screen of this nature may be formed in anysuitable manner as by weaving, using insulating material as either the warp or weft strands and the conductive material as the other strands. Preferably the Nylon is used as a single filament rod or strand which will retain all of the inherent resilient and other properties of the Nylon material rather than as a multifilament strand which may be too flexible and the elastic or resilient qualities of which may be unevenly distributed.

The electrically conductive wires are appropriately connected to opposite terminals and electrically charged in any suitable manner. The mesh should be sufficiently small (and by the construction of my invention may be as small as necessary) so'that any insect walking upon or striking the screen will contact two adjacent oppositely charged wires and receive the charge thereof and thus be electrocuted.

An important object of the present invention, therefore, is to form a screen having the strands running in one direction formed of an insulating material and the strands running in another direction formed of an electrically conductive material.

Another important object of this invention is to construct an insecticidal screen of a fine mesh wherein the strands running in one direction are of insulating material and the strands running in another direction are of electrically conductive material, the insulating material effectively spacing adjacent conductive strands from each other and preventing any effective contact-theretive material.

between no matter how close the approach of the wires may be to each other.

Other objects and uses of the present invention will in part be apparent and in part pointed out in the following description and drawing in which,

Figure 1 is a cross-sectional view of the body portion of a screen made in accordance with my invention.

Figure 2 is a plan view showing an embodiment of one form of my invention in a screen.

Figure 3 is a cross-sectional view on line 3-3 of Figure 2.

Figure 4 is a plan view showing a modified embodiment of my invention wherein the connections of the spaced electrically conductive wires are formed in a modified manner.

Figure 5 is a cross-sectional view on line 5-5 of Figure 4.

Figure 6 is a plan view of a screen of the type of my invention showing a modified form for the electrical connections of the conductive wires.

Figure 7 is a cross-sectional view on line l-'l of Figure 6. g

Figure 8 is a schematic view in perspective showing a manner in which the screen constructions of Figures 2, 4, and 6 may be utilized, showing, however, specifically the construction of Figure 2.

Figure 9 is a schematic view showing one way in which the electrical connections may be made from the current source through the insecticidal screen and associated elements.

Referring now to Figure 1 I have here shown a composite screen made of Nylon and of an electrically conductive material. In this case either the warp or the weft may be of Nylon with intersecting strands of electrically conducwith and space the electrically conductive strands II. The Nylon strands are crimped as at l3-l3 so as to engage the metallic or electrically conductive strands. In this construction it is preferred that the electrically conductive strands ll be likewise crimped in a complementary manner so that should the mesh be deformed by tension or other deforming forces, then upon the relaxation of such tension or deforming force the crimps may tend to slide down their troughs and to assume the complementary registering position maintaining the original mesh definin relationship of the strands.

at that side with the extension 23 of electrically conductive strand 22a.

Similarly along the opposite edge strands 22a and 220 are cut off short at 26 and 21 and strand 22b, which is cut ofi short on the right side at 2!, is extended outwardly on the left side at 23.

The Nylon strands il intersect The only essential element, however, is that i the strands ll space the electrically conductive strands II from each other, and this is accompiished by the woven engagement here shown wherein it is impossible for any electrically con ductive strand to be pressed up against an adjacent electrically conductive strand. This result may be further achieved by ensuring that the strands are sufficiently tight: and the crimps maintaining the resiliently tensed relationship create such a condition.

In Figure 2 I have shown one way in which a screen of the type of Figure 1 may be utilized as a charged screen for insecticidal or other purposes. The screen comprises a series of Nylon warp strands II and a series of electrically conductive weft strands 22. As will be noted the electrically conductive strands 22 extend out- 'wardiy in alternate sta gered relation in such a manner that strand 22a extends beyond the boundary of the screen at 23 while strand 22b is cut oil shorter at the same side at 24, and strand 22c extends outwardly at 2! to be co-extensive It will thus be seen that adjacent strands are staggered at their edges with relation to each other, while alternate strands are co-extensive thusmaking it possible without any difficulty to interconnect alternate strands in the manner shown in Figure 2. This is done for the purpose of facilitating the creation of opposite charges in adjacent strands.

As is seen in Figure 2 a conductive wire is soldered or secured in any other suitable manner to the alternately extended metallic or electrically conductive strands which extend on that side and a metallic wire 3| is soldered or otherwise secured to the alternately extending electrically conductive strands which project on the left side. The wires 30 and 3| are extended up to connection studs 32 and 33 which comprise suitable means, as for instance the screws 34 and 35 by means of which suitable electrical connections may be made. When the terminals 32 and 33 are connected at opposite poles of a current source, then alternate -wires as will be seen in Figure 2 are oppositely charged and insulated from each other by the Nylon strands 2i.

When an insect strikes or walks upon the screen Illitv will establish a connection between two adjacent strands, as for instance 22b and 220 and thus receive the full force of the current and hence be electrocuted. For this purpose'the mesh is sufliciently fine in order to ensure that any insect will cross two electrically conductive wires and hence the view in Figure 2 is a slightly enlarged view of the optimum form of screen for this purpose.

Where the screen is used for other purposes than insecticidal purposes the meshes of the screen It may be of sufiicient size for the particular purpose intended and the wires and the Nylon strands may be of suflicient strength for this purpose. The entire screen 20 may be bound by a suitable frame 40 which may be flexible or not as required in a particular instance. The frame II should along its lateral edges ll and 42 be of a dielectric material so as not toshort-circuit the wires and the frame portions (I and 42 may be utilized, as seen in the cross-sectional view of Figure 3, to secure the connected wire 3| to the electrically conductive strands 22. For this purpose any insulating binding tape may be used or insulating material may be laid in longitudinal stripes Ma and lib on either side of the screen.

In Figure 2 I have shown but one method by which the connection may be made. In the form shown in'Figure 2 it is necessary to cut of! the alternate wires at different points in order to obtain a means of connections or it is necessary to pull alternate connected wires or it may be necessary to otherwise extend the wires in any suitable manner in order to obtain the alternate means hereinabove described.

In Figure 4 I have shown a modified form of screen ill wherein the warp threads ll. are formed of Nylon and wherein double weft threads BI and 52 are used. The ultimate finished form may have a cross-sectional formation similar to that of Figures 2 and 1, but in the weaving operation two shuttles or a double shuttle may be used for carrying the electrically conductive filarnents SI and 52. In such case again alternate spacing strip 80.

oppositely charged.

strands and 52 may be oppositely charged and may for this purpose be connected to connection studs 54 and 55 carrying screws 55 and 51 for the purpose of establishing the electrical connection.

Owing to the fact that the strands cross each other as seen at 58, the strands would short-circuit unless the special provision shown in Figure 5 is made. In this case the curved strand 5ia connecting two alternate strands 5| and the curved strand 52a connecting two alternate strands 52 are separated from each other by being placed on either side of an insulating spacing strip 60. The insulating spacing strip 60 is coextensive with the side of the screen and hence the curved strands ,5la and 52a at each end of each of the electrically conductive strands. which would otherwise contact each other and hence short-circuit, are thus spaced or insulated from each other.

A suitable insulating binding or tape 62 may be adhesively or otherwise placed over the spacing strip 60 and the curved strands 5M and 52a to preserve the finished condition.- Suitable completing frame members may be placed at the edge of the other edges of the screen in order to provide structural support therefor where that '-is needed and in order to prevent unravelling.

, the adjacent strands through any insect or other large flexible netting which may be thrown over extended slightly beyond the screen material at v the edge 13.

As seen in the cross-sectional view of Figure 7 taken in connection with the view of Figure 6 the ends of alternate strands may be bent in opposite directions in order to provide a means for interconnecting alternate strands in order to create oppo'site charges in adjacent strands. Thus a spacing strip 80 is placed beneath the screen at the edge 13 and the ends 01 of each of the strands H is bent downwardly and around the Additional spacing strip 30 is then placed upon the screen at the same edge and the alternate strand I2 are at 32 bent upwardly and around the spacing strip 30. A continuous wire 1.00 is then placed upon the spacing strip 90 and secured in any suitable manner to each of the ends 32 and a similar continuous wire IN is placed upon the spacing strip 80 and suitably secured to and connecting the alternate ends 8| The wires I00 and ID! are then brought up to suitable connecting studs I02 and I03 havin appropriate securing means such as screws I 04 and I05 for effecting electrical connections.

A binding or finishing tape H0 preferably of insulating material is then bound over the edge v to make the connections permanent and any suitable finishing ill for the frame may be applied at the remaining edges of the screen.

In connection with each of the foregoing figures I have described the various ways of making' permanent conductive connections so that by the insulating oppositely oriented strands of Nylon or other insulating material, they can not be brought into contact with each otherand thus make it possible to pass any current present in Since the strands are spaced any object which it is desired to protect. In one form it may be used in connection with a device to attract insects for the purpose of destroying the same and in connection with this in Figure 8 I have shown schematically one embodiment in which the screen 20 of Figure 2 is formed into a cylinder and held in cylindrical position in any suitable manner and a light source 200 is placed within the cylindrical screen for the purpose of providing an attraction for the insects. Any insects seeking to approach the light source will come in contact with the screen and be electrocuted.

For this purpose it may be possible to utilize that form of Nylon or other synthetic insulating material which is either translucent or transparent or in the event that it is determined that any particular color is attractive to insects the Nylon may be translucent and colored appropriately, as for instance a light blue, in order to provide the desired attraction.

In order to insure that the screen will be charged only sufiiciently to destroy insects and not to have any other deleterious effects, it'is preferred that an electric light source be used for the purpose of attraction and the electric light source 'be connected in series with the screen.

Thus, as is shown in Figure 9, suitable electric current source 300 has one terminal thereof connected to a terminal 30| of the apparatus. The current then flows along the wire 302 to the socket 303 into which the light bulb may be inserted. The current enters the socket at the terminal 304, passes through the filament 305 of the light bulb and thence passes to the terminal 306 of the socket. Thence it is connected by the wire 30'! to one terminal 304 of the screen. The opposite terminal 305 of the screen is connected by the wire 308 to the terminal 309 of the main socket of the apparatus, whence the current flows through the wire M0 to the opposite pole of the current source 300.

It will be noted that the screen when an insect short-circuits two adjacent wires thereof is in series with the light bulb. In order to ensure that current will flow constantly through the light bulb 305 a resistance 3 may be connected in shunt across the terminals of the screen. The light bulb is of a nature adapted to th particular current source and is of such resistance so that the voltage in the remainder of the series-circuit is relatively low.

The resistance 3 is sufliciently small so that the voltage drop across adjacent strands of the screen when they are short-clrcuited in any manner is of theorder of not more than 10 volts which would be suilicient to electrocute an insect without having any harmful eiiect of-any nature whatsoever to any individual who may come in contact therewith or to the remainder of the electrical circuit should the wires of the screen be short-circuited.

Where the screen is used as an ordinary window screen or as ordinary netting and not specifically as'an insect trap a similar circuit arrangement such as that shown in Figure 9 may be utilized to eflectively reduce. the charge in the screen so that it will not have any deleterious eflects except upon insects.

I have here shown only a few of the various forms which my invention may take. The electrical connections may be made in many diflerout ways which from the examples above set forth will now be obvious to those skilled in the art. The essential element of my invention comprises the formation of a closely woven screen or mesh wherein the warp or welt strands are oi insulating material and wherein the oppositely oriented strands are oi electrically conductive material and where adjacent electrically conductive strands are oppositely charged.

'Many other objects and uses of this invention will now be apparent to those skilled in the art. I prefer therefore to be bound not by the specific disclosure herein but only by the appended claims.

I claim:

1. A screen having warp and weft strands, one set of strands comprising single filament crimped resilient strands of an electrically insulating synthetic thermally workable material,

said strands having a series or permanently set obtuse angled crimps, the other set of strands comprising electrically conductive wires; saidwires being spaced from each other and positively positioned in predetermined spaced insulating relation by the crimps in the insulating strands.

2. A screen having warp and weft strands, one set of strands comprising single filament crimped resilient strands of an electrically insulating synthetic thermally workable material, said strands having a series of permanently set obtuse angled crimps, the other set of strands comprising electrically conductive wires; said wires being spaced from eachother and positively positioned in predetermined spaced insulating relation by the crimps in the insulating strands; said crimped strands yielding under distorting pressure and automatically returning to their original condition upon release of distorting pressure.

3. A screen having warp and weft strands, one set of strands comprising single filament crimped resilient strands of an electrically insulating synthetic thermally workable material, said strands having a series of permanently set obtuse angled crimps, the other set or strands comprising electrically conductive wires; said wires being spaced from each other and positively positioned in predetermined spaced insulating relation by the crimps in the insulating strands; said crimped strands yielding under distorting pressure and automatically returning to their original condition upon release of distorting pressure; means for connecting alternate wires to the terminal of an electrical current source, and means for connecting the remaining wires to the other terminal of the electrical current source, adjacent wires being oppositely charged.

WILLIAM DUBILIER.

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