US3375124A

US3375124A - Method and apparatus for electrostatically applying flock to filament material

Info

Publication number: US3375124A
Application number: US322092A
Authority: US
Inventors: Linneborn Walter
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-11-07
Filing date: 1963-11-07
Publication date: 1968-03-26
Anticipated expiration: 1985-03-26

Description

w. LINNEBoRN 3,375,124 METHOD AND APPARATUS FOR ELECTHOSTATICALLY APPLYING FLOCK TO FILAMENT MATERIAL 5 Sheets-Sheet 1 8 5 6 e 9 w l 1 7 6 2 v O h N C d Y. a m .1 M F Figp/ March 26, 1968 w. UNNEBORN 3,375,124

METHOD AND APPARATUS FOR ELECTROSTATICALLY APPLYING FLOCK TO FILAMENT MATERIAL Filed Nov. 7, 1963 3 Sheets-Sheet 2 Fig. 3

United States Patent ice METHOD AND APPARATUS FOR ELECTRO- STATICALLY APPLYING FLOCK T FILA- MENT MATERIAL Walter Linneborn, Monschauer-Platz, Cologne, Germany Continuation-in-partof application Ser. No. 11,929, Feb. 29, 1960. This application Nov. 7, 1963, Ser. No. 322,092

Claims. (Cl. 117-17) ABSTRACT OF THE DISCLOSURE Method and apparatus for applying flock under the influence of electrostatic fields produced by two electrodes positioned in a grounded conductive enclosure. Means for moving adhesive-coated filament material at substantially ground potential in longitudinal direction thereof along a predetermined path through a treatment zone within the enclosure. Negatively charged support means arranged below the predetermined path spaced therefrom in transverse direction and adapted for carryin-g flock material particles. Aperture-defining first electrode means through which the particles are adapted to pass, and arranged to apply an electrostatic charge to such particles, the first electrode means being located between the support means and the filament material. Means for establishing between the support means and the first electrode means a first electrostatic field having a first gradient in the transverse direction for effecting movement of the flock material particles in suchv transverse direction. Second electrode means in the encolsure located above the path in substantial parallelism therewith and arranged to apply an electrostatic charge to the flock particles, and means for establishing between the first and second electrode means a second electrostatic field having a second gradient opposite to the first gradient.

This application is a continuation-in-part of my previous application Ser. No. 11,929, filed on Feb. 29, 1960, for Electrostatic Coating of Cord-Like Products, and now abandoned.

The present invention concerns the application of flock material to filament type material and more particularly a method and apparatus for electrostatically applying flock material, particularly short pieces of fibrous material, to adhesive-coated filament material which includes yarns, threads, wires and any other elongated bodies having a comparatively small diameter relative to their length.

Many attempts have been made in the past to apply flock material electrostatically to adhesive-coated filament material. However, the results of the known methods and arrangements have not been satisfactory, mainly for the reason that the applied flock material was not more or less uniformly distributed around the entire circumference of the filament material, but appeared rather to be accumulated more on one side of the filament material than on the opposite side thereof.

It is therefore one object of this invention to provide for a method and apparatus for electrostatically applying flock material to adhesive-coated filament material While avoiding the unsatisfactory -results of the known method and apparatus.

It is another object of this invention to provide for a Amethod and apparatus as set forth which are applicable to various kinds of filament material no matter whether conductive or non-conductive.

It is still another object of this invention to provide for a method and apparatus as set forth which is comparatively simple in operation and entirely satisfactory and efficient in its results.

3,375,124 Patented Mar. 26, 1968 With above objects in view the invention includes a method of electrostatically applying flock material to adhesive-coated material of a diameter comparatively small relative to its length, comprising the steps of: orienting the adhesive-coated material longitudinally in a predetermined direction along a predetermined area of treatment, introducing particles of flock material into a region extending substantially parallel with the predetermined direction and spaced in transverse direction from the adhesivecoated material, subjecting the particles of flock material to a high potential first electrostatic field so directed that the particles of flock lmaterial are moved with substantial acceleration in the transverse direction ltoward the adhesive-coated material so that those of the particles Which make contact with the adhesive-coated material are attached thereto due to the action of the adhesive coating thereof while those other particles which have missed the adhesive-coated material are moved due to the kinetic energy imparted thereto beyond and past the adhesivecoated material, and subjecting the other particles of flock material which have been moved beyond the adhesive-coated material to at least one other electrostatic field so directed that the other particles are caused to reverse their direction of movement and to move in opposite direction toward the adhesive-coated material so that those of the other particles which make contact with the adhesive-coated material are attached thereto due to the action of the adhesive coating while the remaining ones of the other particles which have again missed the adhesive-coated material are caused to be again subjected to the action of the first electrostatic field.

In another aspect the invention also includes an apparatus for electrostatically applying flock material to adhesive-coatedfilament material, comprising, in combination, housing means, moving means for moving adhesive-coated filament material in longitudinal direction thereof along a predetermined path through a predetermined zone of treatment located within the housing means, means for applying to the filament material substantially ground potential, at least partly conductive support means arranged in the housing means and extending substantially parallel with and underneath the predetermined path and spaced therefrom in transverse direction a predetermined distance, for carrying flock material on its top surface, means for applying negative potential to the support means, grid-type electrode means extending substantially parallel with the top surface of the support means and substantially midway between the latter and the predetermined path of the filament material, means for applying high positive potential to said grid-type -electrode means so as to establish a first electrostatic field between the support means and the first electrode means and having a first gradient in the transverse direction and so directed that flock material particles are moved from the support means with substantial acceleration across the grid-type electrode means toward the filament material so that those particles which make contact therewith are attached thereto while those other particles which have missed the filament material are moved beyond and past the latter, second electrode means extending in the housing substantially parallel with and above the pre-determined path of the filament material and spaced therefrom a predetermined distance in the transverse direction, and means for applying negative potential to the second electrode means so as to establish 'a second electrostatic field between the first and second electrode `means and having a second gradient opposite to the first gradient and so directed that the `other flock material particles are caused to reverse the 'direction of their movement and to move in opposite direction toward the filament material so as tot be attached thereto as far as they make contact therewith, while those of the other particles which miss the filament material again are caused to be again subjected to the action of the first electrostatic field.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to itsconstruction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. l is a partly sectional elevation of an apparatus according to the invention, the section lbeing taken along line I--I of FIG. 2;

FIG. 2 is a partly sectional end View of the apparatus according to FIG. l, the section being taken along line II-II of FIG. l;

FIG. 3 is a partial plan view of 4one of the electrodes of the apparatus according to FIGS. l and 2; and

FIG. 4 is a diagram related to the elevation of FIG. 1 and illustrating the execution of the method according to the invention and the operation of the illustrated apparatus.

As can be seen from FIGS. 1 and 2, the apparatus comprises a main housing .1 which surrounds all the operating main components of the apparatus and includes a storage and distribution Iportion 2. The entire housing is constructed as a Faraday cage i.e. it is made predominantly of conductive material and is connected to ground potential at 1". The front and rear walls of the housing 1 are provided each with an opening 1' of rectangular shape as will be described further below.

The storage and distribution portion 2 of the housing 1 serves for the introduction of the fiock material. The portion 2 is separated from the remainder of the housing 1 and is equipped with a funnel 27 for feeding flock material into the interior of the portion 2, a shutter 28 being provided for closing the inlet duct. A rotating distributor brush device 3 with a plurality of arms 4 is rotatably supported in the housing portion 2 and is driven vin a conventional manner by a motor 10 via a speed reduction gear 9 and chain transmissions as illustrated. The individual arms 4 of the brush device 3 may be provided with individual brushes, bristles or with lips or wipers made of rubber or synthetic material so as to brush uniformly over the sieve-like bottom 5 of the housing portion 2 so that any flock material located in the housing portion 2 will be .gradually brushed through the sieve-like bottom 5. In order to render this operation even more effective the center portion 6 of the sieve-like bottom 5 is movable in horizontal direction. This movement is effected by the cooperation of a cam follower 6 attached to the movable portion 6 with a rapidly rotating cam 7 driven through the above-mentioned transmission means also by the motor 10. The sieve-like bottom 5 is suspended on springs as illustrated and is subjected to vertical vibration by the action of auxiliary cams 7' driven in conjunction with the cam 7. Consequently, this vibration movement is superimposed on the reciprocating movement of the center portion 6, which together with the action of the brush device 3 causes the flock material to pass uniformly through the sieve-

like bottom

5, 6 of the housing portion 2.

Extending from a point underneath the sieve-like bottom S in horizontal direction through the housing 1 is an endless `conveyor belt 8 which is made at least predominantly of conductive material and which is in conductive connection with the housing 1 so that the conveyor 8 carries ground or negative potential. 'Ille conveyor 8 is also driven by the motor 10` via the infinitely variable gear transmission 9 and the other transmission means. It is evident that the fiock material passed through the sieve-

like bottom

5, 6 is received by the conveyor 8 and transported in the direction of the arrow in horizontal direction into and through the housing 1. During the travel of the fiock material on the conveyor 8 through the housing -1 the majority of the flock material particles is lifted off the conveyor 8 and applied to the filament material as will be described further below. Whatever flock material is left on the conveyor 8 at its remote end is dropped into a hopper 16 which discharges this material into the intake conduit of a blower 17 also driven by the motor 10 so that this excess material is blown through the duct 18 back into the housing portion 2 for being reintroduced into the operational cycle. The air conveyed through the duct 18 into the housing portion 2 is permitted to escape through a closure 19 which is permeable to air. This closure 19 may consist of an accordion-pleated fabric which is kept in position by rods 20. A twoarm lever tiltably mounted at 21 is so constructed that its lever arm 22 projects into the rotary path of the arms 4 of the brush device 3 so that during the rotation of the brush device 3 the arm 22 is periodically engaged by the arms 4 with the result that the

other arms

24, 25 and 26 periodically strike the fabric of the closure 219 and cause any flock material that may have settled thereon under the action of the air blow to fall back into the housing portion 2.

The filament mate-rial to be covered with fiock material may consist in this example of a plurality of threads of cords 2.9 which are all oriented in a horizontal plane, spaced from each other and guided in horizontal direction through the above mentioned lateral openings 1 of the housing 1 and consequently through the housing 1 at a predetermined distance above the top surface of the conveyor 8. The filaments 29 may be unwound from a reel or reels 32 and pulled through a container 31 grounded at 31 and containing a liquid adhesive 31 so that the filaments 29 pass in adhesive-coated condition through the apparatus for being covered with flock material therein, Whereafter the filaments 29 may be wound on a take-up reel or reels 33 in a conventional manner. Since the ad hesive container 31 assumed to be of conductive material is grounded and since the adhesive itself may be considered to be conductive, and since also the guide rollers guiding the filaments 29 can be assumed to be conductive and connected conductively with the housing 1, it is fair to assume that the filaments 29 carry quasi-ground potential. Should the filaments 29 be made themselves of conductive material then they certainly would carry a potential substantially equal to ground or negative potential.

Extending substantially parallel with the path of the filaments 29 and located substantially midway in transverse direction between the top surface of the conveyor 8 and the path of the filaments 29 is arranged a grid-type electrode 11 as illustrated separately by FIG. 3. The mesh or grating of this electrode 11 is made of conductive material and is held in a frame 11' made of insulating material. The conductive electrode material of the electrode 11 is connected by an insulated connection 34 with a terminal of a source of high positive potential. Consequently, a strong electrostatic field with a gradient in the abovementioned transverse direction is set up between the top surface of the conveyor 8 carrying negative or ground potential and the electrode grid 11 carrying high positive potential. The function of the electrode 11 will be described further below. It should be noted that the electrode 11 or rather its frame 11' is suspended resiliently from the side walls of the housing 1 as illustrated at 11". By cooperation of the frame 11 with pairs of

cams

12 and 13 rotatably supported in the housing 1 as shown in FIG. 2 and driven also by the motor 10 in the same manner as the cam 7 the electrode 11 is subjected to vibratory movement in order to shake loose any ock material particles which may tend to settle on the grid of the electrode 11.

A second grid-type electrode 30 is arranged at a predetermined distance above the plane containing the paths of the filaments 29 and extends in a substantially horizontal plane as illustrated. The grating of the electrode 30 may be similar to that of the electrode 11 except that the openings or perforations thereof may be smaller than those of the electrode 11 and except that the frame 30" holding the grating of the electrode 30 need not be made of insulating material. To the contrary it is desirable to make it of conductive material like the entire electrode 30 so that through the resilient suspension members 30 supporting the frame 30" ground or negative potential is applied to the electrode 30. Consequently, at least one further electrostatic field is set up between the first gridtype electrode 11 carrying high positive potential and the second grid-type electrode 30 carrying negative or ground potential. Pairs of

cams

14 and 15 similar to the

cams

12 and 13, are provided for cooperation with the frame 30 and are also driven in conjunction with the cam 7 so that in this manner also the grid-type electrode 30 is subjected to vibration in order to shake off any fiock material particles that may settle on the grating of the electrode 30.

It must not be overlooked that also potential differences exist between the first grid-type electrode 11 and the opposite wall portion of the housing 1 located above the second grid-type electrode 30, and that, depending upon the actual potential existing on the filaments 29 additional potential differences exist between these filaments 29, the

individual electrodes

11 and 30, the conveyor 8 and the above-mentioned wall portion of the housing 1. All these potential differences necessarily serve to establish corresponding electrostatic fields of correspondingly differing strengths. The existence of these different fields influences in various ways the operation of the apparatus and the action on the flock material particles in accordance with the method devised by the invention.

In carrying out the method according to the invention and in operating the apparatus as described above by Way of example, the procedure is as follows: As is already implied by the above description of the apparatus, ock material is introduced into the housing portion 2 and the ock material particles are continuously fed onto the top surface of the conveyor 8 and carried -by the latter through the interior of the 'housing 1. Simultaneously, filament material is unwound from the stock reel 32 and pulled through the adhesive container 3:1 so as to be coated with adhesive and moved continuously through the interior of the housing 1 in the direction of the arrow in FIG. 2 for being subsequently Wound on the take-up reel or reels 33. The action of the electrostatic fields established in the apparatus will now be explained in full detail by reference to FIG. 4. FIG. 4 is to be considered only as a diagram indicating the positional relations and distances between the top surface of the conveyor 8, the

electrodes

11 and 30, the plurality of filaments 29 and the top wall of the housing 1. Also, this diagram indicates the polarities of the electric potentials applied .to the abovementioned portions of the arrangement (as indicated at the left hand side of the diagram) and also the various electrostatic fields set up on the basis of the existing potential differences lbetween the above-mentioned components of the arrangement.

The various fields are marked with the rom'an numerals LVII. Wherever within the diagram a marking occurs like II-VII this does not mean to represent the difference between the strength of the fields II-VII, but meansfthat at the particular point all the fields numbered II to VII exert their inuence. In a similar manner, where in the diagram an indication occu-rs like IV-i-VI .this does not mean ythat here the two fields IV and VIv are additively superimposed upon each other but this means only that at the particular point both the fields IV and VI exert their effect.

For the purpose of explanation only the entire horizontal length of the diagram is subdivided into sectors numbered l to 20 so that different phenomena that may occur anywhere within the existing electric fields may be described with reference to specific illustrations in the, individual sectors mentioned above.

May it be assumed that it is desired to describe what happens to a fiock material particle A which is placed on the conveyor 8 and introduced into the area of treatment at the right hand end of the diagram. Since it is proper to assume that this particle A is electrically neutral it is shown as an empty rectangle lying fiat on the surface of the conveyor 8.

Sector I As soon as the particle A enters the sector 1 it is exposed to and influenced by .the strong electrostatic field I existing lbetween the conveyor 8 and the positively charged electrode 11 so that the particle A is oriented in vertical direction, i.e., in direction of the existing gradient and is accelerated in vertical direction.

Sector Z After the particle A has been set in motion there are only two possibilities. The first possibility is that the particle A darts through one of the openings of the grid-type electrode 11, the other is that it hits one of the grid wires or the like as is shown in sector 17. The particle which, as shown in sector 2, passes through an opening of the positively charged grid-type electrode 11 is thereby charged itself to positive potential under the infiuence of the field I. Therefore, in sector 2 the particle A is shown as a solid black rectangle. Referring now also to sector 17, it will be understood that upon hitting a grid wire of the electrode 11 the particle A is also charged to positive potential with the result that it now possesses the same polarity as the electrode 11. Consequently, the particle A in sector 17 is subject to two forces, namely to the force of repulsion K from the electrode 11 and to the force of gravity G. Consequently, this charged particle A drops back onto the top surface of the conveyor 8 as shown in sector 18, where it is discharged which is indicated by illustrating the particle in sector 18 half white and half black. It will be explained 'later that the particle as shown in sector 18 meets the same conditions as the particle A in sector 1 so that it is in this manner re-introduced into the operational cycle.

Sector 3 A fiock material particle A which as shown in sector 2 has been shot or propelled through one of the openings of the grid-type electrode 11 and continues its movement in an upward direction on account of the kinetic energy imparted thereto is now under the diversified influence of all the electrostatic fields II-VII. Upon reaching the plane comprising the paths of the filaments 29 it may be subject to one of several possibilities. The first possibility is illustrated in sector 3, namely the possibility that this particle A directly hits or makes contact with one of the filaments 29. It may be partly .or wholly 'discharged upon contact but in any case it will be attached to the particular filament on the side facing the electrode 11 on account of the adhesive coating of the filament.

Sector 4 A second possibility is illustrated in sector 4. In this case, the positively charged particle A does not directly hit a filament 29 bu-t it tends to pass by the filament 29 on its right lhand side so closely that the forces of attraction between the positively charged particle A and the filament carrying quasi-ground potential or negative potential take effect so that in allprobability the rear end of this particle makes contact with the particular filament 29 whereby further upward movement of this particle is stopped.

Sector 5 Now the force of gravity in addition to electrostatic attraction by one or the other of the neighbouring filaments 29 causes the particular iiock material particle to tilt over and to assume for instance a position as shown in sector 5. However, likewise other positions may result as illustrated by Way of example in sectors l2 and 13. Already from the above it can be seen that the various 7 particles A of short pieces of elongated fibrous material will be attached to the adhesive-coated filament 29 in a great number of different positions oriented radially in many directions relative to the particular filament.

Sector 6 A further possibility consists in the particular fiock material particle A passing at comparatively high speed exactly in the middle between two neighbouring filaments 29 so that the attractive forces of these two filaments compensate each other. Consequently, this particle being still positively c-harged will travel under the influence of at least the electrostatic fields IV and VI in upward direction. Again, there are various possibilities. The first possibility is that as shown in sector 6 the particle passes through one of the openings of the second grid-type electrode 30 which carries negative or ground potential. If the particle passes more or less exactly through the center of that opening of the electrode 30 its movement will continue in upward direction toward the top wall of the housing 1.

Sector 7 The top wall of the housing 1 carries ground i.e., negative potential. Consequently, when the flock material particle A impinges on the grounded top wall it is discharged.

Sector 8 As a consequence, the completely discharged particle is now subjected only to the torce of gravity G and drops in direction toward the electrode 30.

Sector 9 The possibility that the dropping particle A cornes to rest on a solid portion of the grid-type electrode 30 is not illustrated in the diagram because it is without any interest in the context of the consideration of the electrostatic phenomena. As mentioned further above, the electrode 30 is continuously vibrated so that it is to be expected that sooner or later such a particle will be moved into a position where it will fall through one of the openings of the electrode 30. This, however, is a condition identical With that existing when the dropping particle as illustrated in sector 8 drops directly through one of the openings of the electrode 30. If, on its downward path, it makes direct contact with one of the filaments 29 it will become attac-hed thereto on account of the adhesive coating thereof, and assume a position similar to those illustrated in sectors 11-13, 15, and 16. However, it might as well drop further down, passing between two neighbouring filaments 29 and reach the region of the positively charged electrode 11. It may make contact directly with a solid portion of the electrode 11 or be attracted thereto, in either case it will immediately be charged to positive potential thereby. Consequently, having now the same polarity as the electrode 11, it will be subject to repulsive forces K so that this particle is again accelerated in upward .direction as indicated in sector 9. In addition at least the electrostatic field 1I takes effect because the filaments 29 carry quasiground or actual ground potential whereby the positively charged particle is attracted.

Sector If this particle which was started in upward direction as shown in sector 9 directly hits a filament 29 as s-hown in sector 10 it will be rattached to its lower side in the same manner as has been discussed above in reference to the occurrences in sectors 2 and 3. However, also the conditions discussed and explained above in reference to

sectors

4 and 5 may take place so that the particle may be attached to filaments 29 in the manner illustrated in

sectors

5, 12, 13, 15 or 16. Actually, the particle illustrated in sector 9 is under the diversified influence of all the fields II-VII.

8

Sectors

11, 12 and 13 As mentioned above,

sectors

11, 12 and 13 illustrate various positions which the particle A may assume after being attached to one of the filaments 29 after it has passed closely by one of these filaments as explained above in reference to

sectors

4 and 5.

Sector 14 The particle A as discussed in reference to sector 9 may continue its movement in upward direction beyond the plane of the filaments 29 and reach the region of the second electrode 30.

Again it may pass through one of the openings thereof, in which case, the conditions will prevail which have been discussed above in reference to sectors 6-8. However it may as well make contact with a solid portion of the grid-type electrode 30l as illustrated in sector 14. Since the electrode 30 carries ground, i.e. negative potential, the positively charged particle A will be discharged upon contact with the electrode 30 and will be neutralized in the same manner as described above in reference -to sectors 7 and 8. Consequently, all the consequences may take place which have been described above in this connection. At least the particle shown in sector 14 will be subjected to the force of gravity G so that it will drop down with the consequence that it is either directly attached to one of the filaments 29 or reaches again the area of the electrostatic fields I and Il, in which case it re-enters the operational cycle described above.

Sectors

15 and 16 The conditions existing in sectors l5 and 16 have been discussed above so that no repetition -is needed at this point.

Sector 17 As mentioned already further above, in connection with the occurrences in

sectors

1 and 2, sector 17 illustrates the conditions existing when the particle A accelerated in upward directions so as to move from the top surface of the conveyor 8 toward the electrode 11, would make contact with a solid portion of the electrode 11. If this should occur, the particle is also immediately charged to the positive potential of the electrode 11. Consequently, it Will be repulsed therefrom, and simultaneously subjected to the force of gravity as indicated by the arrow and the symbols K and G. Thus, it is rapidly returned to the top surface of the conveyor 8.

Sector .7 8

As indicated in sector 18 the particle is consequently discharged and is in the same condition which has been described in reference to sector 1. Thus, it will be re-introduced into the cycle of operation.

Sector 19 The illustration in sector 19 is intended only to show that in view of the above various possibilities at least those ock material particles A which hit directly one of the filaments 29 will be attached thereto in opposite directions, one at the lower side and one at the upper side of the particular filament.

Sector 20 Finally the illustration in sector 20 is intended to show that as a result of all the above described electrostatic effects on the thousands or millions of particles A, it can be safely expected that a filament 29 will be covered from all sides with flock material particles exactly as was desired at the outset.

Of course, it will be understood that not all the particles Iwill travel strictly along straight vertical lines upward or downward. There may also be collisions between particles, a reflection of mechanical nature of a particle when it hits the inclined top surface of the housing 1 and the like. However, these irregularities of movements do not affect in any way the general operation according to the method devised by the invention. In addition, it must be borne in mind that the individual particles as they rnove around within the housing 1 are in a varying manner subjected to the varying influences of the various electrostatic fields I-VII, the effects on individual particles are superimposed upon each other in varying degrees at different points within the housing 1. All these accumulated effects serve advantageously the main purpose and object of the invention, namely to cause a more or less uniform application of flock material to all sides of the individual filaments or the like.

It should be noted that it is a great advantage of the present invention that actually all the potential differences or electrostatic fields which are utilized in the process are generated by the positive charge of only one electrode, namely the grid-type electrode 11. All other active members of the arrangement which take partV in the electrostatic action namely the conveyor 8, electrode 30 and the top wall of the lhousing 1 carry ground, i.e. negative potential. The filament material itself contributes to the electrostatic action inasmuch as it either carries quasiground potential or, if the filament material is conductive, ground potential like the above-mentioned electrode 30.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other tppes of a method and apparatus for electrostatically applying fiock material to material of a diameter comparatively small relative to its length, differing from the types described above.

While the invention has been illustrated and described as embodied in a method and apparatus for electrostatically applying flock material to adhesive-coated filament material, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this in-vention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A method of electrostatically applying fiock material to adhesive-coated material of a diameter comparatively small relative to its length, comprising the steps of:

orienting the adhesive-coated material longitudinally in a predetermined direction along a predetermined area of treatment;

introducing particles of flock material into a region extending substantially parallel with said predetermined direction and spaced in transverse direction from said adhesive-coated material;

subjecting said particles of flock material to a high potential first electrostatic field which is stationary in space and so directed that said particles of flock material are moved with substantial acceleration in said transverse direction toward said adhesive-coated material so that those of said particles which make contact with said adhesive-coated material are attached thereto due to the action of the adhesive coating thereof while those other particles which have missed said adhesive-coated material are moved due to the kinetic energy imparted thereto beyond and past said adhesive-coated material;

and subjecting said other particles of flock material which have been moved beyond said adhesive-coated material to at least one other electrostatic field which is stationary in space and so directed that said other particles are caused to reverse their direction of movement and to move in opposite direction toward said adhesive-coated material so that those of said other particles which make contact with said adhesivecoated material are attached thereto due to the action of said adhesive coating while the remaining ones of said other particles which have again missed said adhesive-coated material are caused to be again subjected tothe action of said first electrostatic field.

2. A method of electrostatically applying fiock material to adhesive-coated filament material, comprising the steps of:

moving the adhesive-coated filament material longitudinally in a predetermined direction along a predetermined path through a predetermined area of treatment;

introducing particles of ock material into a region extending substantially parallel with said predetermined path and spaced in transverse direction from said adhesive-coated filament material;

subjecting said particles of fiock material to a high potential first electrostatic field which is stationary in space and so directed that said particles of flock material are moved with substantial acceleration in said transverse direction toward said adhesive-coated filament material so that those of said particles which make contact with said adhesive-coated filament material are attached thereto due to the action of the adhesive coating thereof while those other particles which have missed said adhesive-coated filament material are moved due to the kinetic energy imparted thereto beyond and past said adhesive coated filament material;

and subjecting said other particles of flock material which have been moved beyond said adhesive-coated filament material to at least one other electrostatic field which is stationary in space and so directed that said other particles are caused to reverse their direction of movement and, to move in opposite direction toward said adhesive-coated filament material so that those of said other particles which make contact with said adhesive-coated filament material are attached thereto due to the action of said adhesive coating while the remaining ones of said other particles which have again missed said adhesive-coated filament material are caused to be again subjected to the action of said first electrostatic field.

3. A method of electrostatically applying fiock material to adhesive-coated filament material, comprising the steps of:

moving ad-hesive-coated filament material having substantially ground potential in longitudinal direction thereof along a predetermined path through a predetermined zone of treatment;

maintaining in a first limited area extending substantially parallel with said direction of movement but being spaced in transverse direction a predetermined distance from said path of said filament material a first electrostatic field which is stationary in space, said electrostatic field having a first gradient in said transverse direction between a first boundary having high positive potential and a second boundary having negative lpotential;

introducing fiock material into the region along said second boundary having negative potential so as to cause particles of said fiock material to be moved by electrostatic attraction with substantial acceleration in said transverse direction to said first boun' dary having high positive potential and to be moved due to said acceleration further beyond said first boundary toward said filament material so that any thus moved particle of flock material which makes contact with said filament material is attached thereto by the action of the adhesive coating thereof, while 1l those other flock material particles which have missed said filament material are moved due to the kinetic energy imparted thereto beyond said path of said filament material; and

maintaining in a second limited area adjacent to said first area and encompassing said zone of treatment and said path of said filament material at least one second electrostatic field which is stationary in space, said electrostatic field having a second gradient in said transverse direction between said first boundary which is common to both said areas and has high positive potential, and a third boundary having negative potential, the direction of said second gradient being opposite to that of said first gradient, so as to cause said other flock material particles which have been moved beyond said path of movement of said filament material to reverse their movement and to move in opposite direction toward said filament material so as to be attached thereto as far as they make contact therewith, while those of said other particles which again miss said filament material are caused to return to either one of said first and second boundaries of said first electrostatic field and to repeat their movement toward said filament material.

4. Apparatus for electrostatically applying fiock material particles to adhesive-coated filament material, comprising, in combination, grounded conductive enclosure means; moving means for moving adhesive-coated filament material at substantially ground potential in longitudinal direction thereof along a predetermined path through a treatment zone within said enclosure means; negatively charged support means arranged in said enclosure means and extending below said predetermined path spaced therefrom in transverse direction, said support means having a top surface in substantial parallelism with said path and adapted for carrying fiock material particles thereon; aperture-defining first electrode means through which said flock material particles are adapted to pass and arranged to apply an electrostatic charge to such particles, said first electrode means extending substantially parallel with said path substantially midway between said top surface and said filament material; means for establishing between said support means and said first electrode means a first electrostatic field having a first gradient in said transverse direction for effecting movement of said flock material particles in said transverse direction and at substantial acceleration from said support means through said first electrode means and toward said filament material so that those particles which make contact therewith are attached thereto, while other particles which fail to contact said filament material move beyond the latter; second electrode means extending in said enclosure means in substantial parallelism with said path upwardly spaced therefrom in said transverse direction, said second electrode means having a plurality of openings and being arranged to apply an electrostatic charge to said other flock particles; and means for establishing between said first and secon-d electrode means a second electrostatic field having a second gradient opposite to said first gradient for effecting reversal of the movement of said other fiock particles to thereby cause the same to move in opposite direction toward said filament material, whereby those of said other flock particles which contact said filament material become attached thereto, whereas the remaining flock particles which fail to contact said filament material are again subjected to the action of said first electrostatic field.

5. Apparatus for electrostatically applying flock material to adhesive-coated filament material, comprising, in combination,

grounded conductive housing means;

moving means for moving adhesive-coated filament material in longitudinal direction thereof along a predetermined path through a predetermined zone of treatment located within said housing means:

means for applying to said filament material substantially ground potential;

at least partly conductive support means arranged in said housing means and extending substantially parallel with and underneath said predetermined path and spaced therefrom in transverse direction a predetermined distance, for carrying flock material on its top surface;

means for applying negative potential to said support means; grid-type first electrode means through which said flock material is adapted to pass, said first electrode means being arranged for applying an electrostatic charge to said fiock material and extending substantially parallel with said top surface of said sup-port means and substantially midway between the latter and said predetermined path of said filament material;

means for applying high positive potential to said gridtype electrode means so as to establish a first electrostatic field between said support means and said first electrode means and having a first lgradient in said transverse direction and so directed that flock material particles are moved from said support means with substantial acceleration through said grid-type first electrode means toward said filament material so that those -particles which make contact therewith are attached thereto while those other particles which have missed said filament material are moved beyond and past the latter; second electrode means having a plurality of openings,

said second electrode means extending in said housing substantially parallel with and above said predetermined path of said filament material and spaced therefrom a predetermined distance in said transverse direction; and means for applying negative potential to said second electrode means arranged for applying an electrostatic charge to said other particles and so as to establish a second electrostatic field between said first and second electrode means and having a second gradient opposite to said first gradient and so directed that said other fiock material particles are caused to reverse the direction of their movement and to move in opposite direction toward said filament material so as to be attached thereto as far as they make, contact herewith, while those of said other particles which miss said filament material again are caused to be again subjected to the action of said first electrostatic field. 6. Apparatus as claimed in claim 5, wherein said housing means are constructed as a Faraday cage.

7. Apparatus as claimed in claim 6, wherein said gridtype first electrode means is provided with openings larger than the openings of said second electrode means.

8. Apparatus for electrostatically applying flock material to adhesive-coated filament material, comprising, in combination,

grounded conductive housing means; moving means for moving adhesive-coated filament material in longitudinal direction thereof along a predetermined path through a predetermined zone of treatment located within said housing means;

means for applying to said filament material substantially ground potential;

at least partly conductive conveyor means arranged in said housing means and extending substantially parallel with and underneath said predetermined path and spaced therefrom in transverse direction a predetermined distance, for carrying fiock material on its top surface through said housing;

means for applying negative potential to said conveyor means;

grid-type first electrode means through which said flock material is adapted to pass said rst electrode means Ibeing arranged for applying an electrostatic charge to said flock material and extending substantially parallel with said top surface of said conveyor means and substantially midway between the latter and said predetermined path of said filament material;

means for applying high positive potential to said gridtype electrode means so as to establish a rst electrostatic leld between said conveyor means and said first electrode means and having a first gradient in said transverse direction and so directed that flock material particles are moved from said conveyor means with substantial acceleration through said gridtype first electrode means toward said filament material so that those particles which make contact therewith are attached thereto while those other particles which have missed said filament material are moved beyond and past the latter;

second grid-type electrode means arranged for applying an electrostatic charge to said other particles, and eX- tending in said housing below a wall of said housing means and substantially parallel with and above said predetermined path of said filament material and spaced therefrom a predetermined distance in said transverse direction; and

means for applying negative potential to said second means and a third electrostatic field between said first housing means so as to establish a second electrostatic ield between said first and second electrode means and a third electrostatic field between said first electrode means and said wall of said housing means, said fields having a second and a third gradient, respectively, opposite to said iirst gradient and so directed that said other flock material particles are .caused to reverse the direction of their movement and to move in opposite direction toward said filament material so as to be attached thereto as far as they make contact therewith, while those of said other particles which miss said filament material 4 again are caused to be again subjected to the action of said first electrostatic field. 9. Apparatus as claimed in claim 8, including vibrator means for applying oscillatory movement to said first and second grid-type electrode means.

10. Apparatus as claimed in claim 9, wherein said housing means are constructed as a Faraday cage.

11. Apparatus as claimed in claim 10, wherein said rst grid-type electrode is provided with openings larger than the openings of the second grid-type electrode.

12. Apparatus as claimed in claim 9, wherein said first grid-type electrode is provi-ded with openings larger than the openings of the second grid-type electrode.

13. Apparatus as claimed in claim 8, wherein said housing means are constructed as a Faraday cage.

14. Apparatus as claimed in claim 12, wherein said first grid-type electrode is provided with openings larger than the openings of the second grid-typeelectrode.

15. Apparatus as claimed in claim 8, wherein said first grid-type electrode is provided with openings larger than the openings of the second grid-type electrode.

References Cited UNITED STATES PATENTS Re. 22,419 1/1944 Smyster 117-17 2,047,525 7/1936` Thode 117-17 2,152,077 3/1939 -Meston et al 117-17 2,173,032 9/1939 Wintermute 117-17 2,174,328 9/1939 Meston et al. 117-17 2,276,328 3/1942 Melton 118-627 2,675,330 4/1954 Schwartz et al. 117-33 X 2,698,814 1/ 1955 Rausburg 118-624 X 2,976,839 3/1961 Okma et al. 118-624 X 3,096,213 7/ 1963 McCurtain 118-638 2,986,473 5/ 1961 Ritzerfeld et al. 117-17 X FOREIGN PATENTS 479,254 12/1951 Canada. 1,002,725 2/ 1957 Germany.

337,486 5/ 1959 Switzerland.

0 WILLIAM D. MARTIN, Primary Examiner.

MURRAY KATZ, Examiner.

E. I. CABIC, Assistant Examiner.