US3459613A - Method and apparatus for making filamentous mat - Google Patents

Description

1959 J. E. COPENHEFER ETAL 3,459,613

METHOD AND APPARATUS FOR MAKING FILAMENTOUS MAT Filed July 29, 1965 INVENTOR. John E. C'apenhe/er George J. //efi 3,459,613 METHOD AND APPARATUS FOR MAKING FILAMENTOUS MAT John E. Copenhefer and George J. Heb, Louisville, Ky.,

assignors to American Air Filter Company, Inc., LOUIS- ville, Ky., a corporation of Delaware Filed July 2, 1965, Ser. No. 475,650 Int. Cl. D04h 3/16 US. Cl. 156167 5 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for the manufacture of fibrous mats including selective variation of the spacing between filaments wound on a rotating filament collector drum and apparatus to decrease the amount of material deposited at the ends of a fibrous mat formed on a rotating drum.

BACKGROUND OF THE INVENTION A well-known method and apparatus for formation of condensed mats of, for example, glass, comprises reciproeating a filament feeding apparatus in a traverse axially along a rotating drum. Molten glass issues through multiple orifices in the bottom of the feeder and the streams issuing therefrom are attenuated into glass fibers by winding upon the rapidly rotating drum. The furnace is reciprocated back and forth across the length of the drum a plurality of times to form a mat composed of a plurality of layers of spun fibers, the layers extending substantially from one to the other end of the drum. When sufiicient traverses of the furnace have been effected to build the mat to the desired thickness, the collected mat is slit parallel to the axis of rotation of the drum and removed therefrom as a sheet. The sheet can then be expanded by stretching the same transversely to the line of slit.

A disadvantage frequently common to previous methods and apparatus for manufacturing such mats is that fewer fibers are deposited on the drum in the end reversal areas of the furnace traverse. This occurs because the furnace stops momentarily at each end of the traverse and all of the openings in the orifice plate do not pass completely over the drum in the end reversal areas to deposit the same number of filaments as are deposited in the central portions of the drum. Increasing furnace dwell time in the end reversal areas deposits more glass, but the characteristics of the material thus formed are different from the characteristics of the material in the central portion of the mat. The material formed in the end reversal areas is generally of inferior quality and considered scrap material to be discarded as waste.

In certain applications it is desirable to manufacture a condensed mat of varying density throughout the thickness of the mat. This objective is currently accomplished, among other methods, through the use of collector wheels to collect mono-filaments of glass to form multi-strand filaments for deposition on the rotating drum, or through the device of slowing the speed of rotation of the rotating drum during the formation of the mat to form filaments of larger diameter.

In accordance with the present invention, a novel and useful method and apparatus for manufacturing filamentous glass mats is provided wherein the waste normally associated with the portion of the mat formed in the end reversal areas of the traverse is materially reduced and a method is provided to vary mat density in any desired manner throughout the thickness of the mat without the use of abrasive glass contacting devices or collectors. Fur- States Patent 0 e we ther, the present invention provides a method of accomplishing both desirable objectives simultaneously and cooperatively without sacrificing the effectiveness of either objective.

Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth hereinafter.

More particularly, the present invention provides a method of making a condensed, filamentous mat of a plurality of layers of fibers wherein a filament feeding apparatus is transversely reciprocated axially along a rotating drum, filaments are discharged from multiple openings in the feeder and collected on the rotating drum. The filaments are collected on the rotating drum to build a cylindrical mat composed of a succession of layers of fibers with each layer composed of a multiplicity of helical turns of fibers and extending generally from one end of the rotating drum to the other.

In accordance with the present invention, during the formation of the filamentous mat the filament feeder can be disposed at more than one position of angular displacement with relation to the rotating drum, the angle measured being determined by the position of the axis of rotation of the drum with respect to the position of the longitudinal axis of the filament feeder. With such an arrangement, it is possible to collect the fibers into collected fiber filaments or strands as the longitudinal axis of the furnace moves toward a substantially perpendicular position relative the rotational axis of the drum. This collection of filaments with more than one position of angular displacement yields a mat product of graded density.

Further, in accordance with the present invention, the traversing speed of the feeder drive means can be varied throughout the formation of the filamentous mat, and in particular, can be increased during the time when the filament feeder is in the end reversal areas of the drum to materially reduce the residence time of the feeder in the end reversal areas and thus materially reduce the amount of glass deposited in the end reversal areas of the traverse.

The present invention further provides for formation of filamentous mats of variable density in still a further manner wherein the traversing speed of the reciprocating furnace can be changed relative the speed of the drum in a preselected manner during the formation of a unit mat, regardless of the location of the feeder in its traverse and regardless of the aforementioned angular displacement. In accordance with the present invention, the preselected speed change results in a deposition of fibers onto the drum at preselected differing angles of lay with such differing angles of lay causing certain fibers to group together upon expansion of the mat so as to produce varied density in the completed mat.

Referring to the drawing which discloses one advantageous embodiment of the present invention.

FIGURE 1 is an elevational view of an apparatus used to manufacture filamentous mats taken from the end of the rotating drum, showing the longitudinal axis of the filament feeder in angular relation with respect to the longitudinal axis of the rotating drum;

FIGURE 2 is an elevational view taken from the front of the rotating drum;

FIGURE 3 is a horizontal view showing orientation of the gear adjusting mechanism for the feeder assembly; and

FIGURE 4 is an enlarged, partial view of a sprocket taken in a plane passing through line 44 of FIGURE 1.

Referring to the drawings, there is shown a generally horizontal drum 1 which is normally rotated at high speed (by means not shown) whereon filaments 4 are collected to form a condensed mat. Furnace 2, containing suitable molten material, for example glass, has in the bottom side thereof a plate (not shown) including a multiplicity of orifices through which said molten material issues to form filaments 4. The orifices in said plate can be arranged in any desired geometrical configuration but usually there are longitudinally-extending rows of orifices in the plate, and in the normal apparatus, each row can contain 50 orifices with the rows spaced approximately one inch apart. The diameter of filaments 4 drawn from the furnace 2 to the rotating drum 1 is influenced by the rotational speed of drum 1. Filaments are drawn to the drum as individual monofilaments, or as strands composed of a number of monofilaments, depending upon the proximity of adjacent filaments as drawn from the filament feeder, Furnace 2 is supported from furnace carriage 10 by yoke 3 mounted on shaft 6 affixed to rtatable support plate 8. Support plate 8 is rotatably mounted within and to carriage 10 to turn furnace 2 to any desired angular relation with respect to the rotational axis of rotating drum 2.

Gear teeth are provided around the periphery of support plate plate 8. These teeth cooperate with worm gear 7 aifixed to shaft 20 mounted in worm gear shaft bracket 21. Handle 9, affixed to shaft 20, serves to permit manual turning of shaft 20 and worm gear 7 to orient the longitudinal axis of the furnace relative to the longitudinal axis of the rotating drum 1 in any desired angular relation. Furnace carriage is mounted on wheels 11 disposed in cooperative spaced relation to move on tracks 12. Tracks 12 are disposed in straddling relation above a downturning edge of the rotating drum 1 and extend generally parallel the longitudinal axis of the drum to carry the furnace carriage 10 in reciprocatory traverses along said downtuming edge. Variable speed furnace drive means 17 is provided to move furnace carriage 10 and furnace 2 along tracks 12. Drive means 17 includes motor 18 and variable speed gear box 19 which is connected to turn sprocket 16 to drive endless chain mounted around it and idler sprocket 22 at a preselected speed. The speed of the furnace drive means transmitted to sprocket 16 can be controlled by a variable rheostat (not shown) in the power line to the motor 18, or by integral speed changing mechanism (not shown) in the variable speed gear box 19. Any desired means such as a time clock (not shown) may be used to control the rheostat or the variable speed gear box to change the speed of the furnace drive means 17. Drive pin 14 is afiixed to chain 15 and nests in a vertically-extending pinreceiving slot 13 on arm 13 which is mounted to furnace carriage 10. Pin 14 is free to move in a vertical direction in slot 8 while driving the furnace carriage 10 in a generally horizontal direction on tracks 12 in response to the movement of chain 15, For example, the pin moves along with chain 15 in a horizontal direction between sprocket 16 and 22 and drives the furnace correspondingly. The pin then moves around the sprockets and during the period when pin 14 is moving around a sprocket and in a generally vertical direction in the slot, there is a correspondingly decreased horizontal motion of the furnace 2. Further movement of pin 14 reverses the direction of horizontal travel of furnace 2, and pin 14 once again resumes a generally horizontal movement corresponding to travel between sprockets. The portion of the traverse during the period when drive pin 14 is passing around a sprocket is best described as the end reversal area of the furnace traverse. The portion of the mat formed during the period when the furnace is in the end reversal areas of the traverse is usually of less desirable quality than the part of the mat formed when the furnace is in the central portion of the rotating drum because all of the orifices of the furnace do not pass over the end reversal areas to deposit filaments, so there is less glass deposited in the end reversal areas than in the central portion of the mat, and the edge portions are further undesirable because of undesirable angles of lay of the fibers due to furnace speed changes. It will be realized by those skilled in the art that any other suitable means may be used as a furnace drive means 17 hereinbefore illustrated without affecting the scope or intent of the present invention.

In operation, the drum 1 is rotated at a desired speed and chain 15 moves pin 14 at a speed determined by the preselected speed of the variable speed drive means 17, the furnace 2 being driven accordingly. The width of the mat formed on rotating drum 1 is determined by the length of the furnace traverse.

In one advantageous example, the speed of furnace drive means 17 is changed relative the drum speed periodically regardless of the position of the feeder in the traverse, and a mat is formed of fibers, a portion of which have one angle of lay and at least another portion of which has another angle of lay. It is to be understood that this can be done in a number of ways as described hereinafter and it further is to be understood that the preselected periodic change can occur at any location of the filament feeder in its traverse. For example, the furnace can be run for a preselected period of time (one houras an illustration) at a constant speed relative the drum speed. Then for another preselected period of time (onehalf hour, for example) the furnace can be run on a cycle, combining two preselected but different speeds relative to the drum speed which deposits fibers on the drum at two different angles of lay. One of these two preselected speeds can be approximately equal to the original speed and the other can be less. During subsequent preselected periods of time (one-half hour each, for example) the percentage of time of the lesser of the two pre-selected speeds can be increased. It is to be understood that the present invention is not to be considered as limited to the specific cycling arrangement aforedescribed and that the lower speeds can be taken to zero or standstill without detriment to the concept of the present invention. It further is to be understood that, as is known in the art, suitable binder materials can be applied to the mat during or after its formation. If the mat thus formed is subsequently cut parallel to the longitudinal axis of the drum and expanded by drawing or stretching it from one of its edges, which extends in the general direction of the fibers, an expanded mat results wherein those fibers deposited at a greater angle of lay, corresponding to a higher relative speed between feeder and drum, are substantially straightened, and those fibers deposited at a lesser angle of lay loop or curl and are grouped to provide graded mat density as a function of such grouping. The density of a mat thus formed changes incrementally throughout the thickness of the mat.

As aforestated, the portion of the mat formed in the end reversal areas of the traverse has been generally considered waste and therefore discarded. By the advantageous method herein disclosed, the amount of waste formed in the end reversal areas is reduced by decreasing the time the furnace is in the end reversal areas, thereby reducing the amount of glass deposited and to be wasted in the end reversal areas. The speed of furnace drive means 17 is increased when pin 14 approaches sprocket 16 or 22 and the furnace 2 is entering the end reversal areas of the traverse as can be seen in FIGURE 4. The speed increase of the drive means can be accomplished through use of limit switches 23 and 24. Switch 23 initiates an increase in speed of furnace drive means 17 when pin 14 engages the lever of the switch 23 to actuate a control mechanism such as, for example, a cooperating rheostat (not shown in detail) in a suitable power supply circuit 25 to motor 18. As pin 14 leaves the sprocket, it contacts the lever of switch 24 which causes said furnace drive means to resume normal speed by actuating the rheostat in the power circuit 25 in a reverse direction. The decreased residence time of the furnace in the end reversal portions of the traverse results in the deposition of fewer fibers in these areas of the drum than would normally occur without increasing the speed of the furnace traverse, and since the portions of the mat formed in the end reversal areas are discarded as waste, the total amount of glass discarded as waste is decreased. It will be understood that a similar action obtains at the other end of chain 15 due to another set of switches 23 and 24'.

As shown in the drawing, furnace 2 is pivotally mounted on the furnace carriage by means of rotatable plate 8 and shaft 6, and the longitudinal axis of the furnace can be turned in angular relation to the longitudinal axis of the drum by turning worm gear 7. Handle 9, attached to worm gear 7 by shaft 20, can be turned as desired to manually adjust the angular position of the furnace. It will be realized by one skilled in the art that gear 7 can be continuously turned during the formation of the condensed mat either manually or by any suitable means to continuously change the angular relation between the longitudinal axis of furnace 2 and drum 1.

The width of the waste portion of the mat formed in the end reversal areas is approximately equal to the width of the band of filaments 4 wound on the drum. Thus, if the longitudinal axis of the furnace orifice plate is parallel the longitudinal axis of the drum, the width of the waste portion formed is approximately equal to the width of the furnace 2 plus the radius of the sprocket 16 or 22. As is known in the art, the amount of waste formed in the end reversal areas of the mat is reduced by decreasing the width of the band of filaments 4 wound on drum 1. In most furnaces reduced waste will result when the longitudinal axis of the furnace is at an angle other than parallel to the longitudinal axis of the drum. In addition to the waste reduction at the end areas of the drum as a result of effecting a preselected angular relation other than parallel between the longitudinal axis of furnace 2 and drum 1 at such end areas, the present invention recognizes that angular variation intermediate the end reversal areas provides for variable fiber grouping with resulting formation of a condensed mat of variable density throughout the thickness of the mat when the mat is expanded. A portion of such mat can be formed with the longitudinal axis of the reciprocating furnace 2 at substantially less than a right angle with respect to the longitudinal axis of the rotating drum. Another portion of the mat can be formed with the longitudinal axis of furnace 2 at an increased angular relation approaching a right angle to the longitiudinal axis of rotating drum 1. The portion of the mat formed with the longitudinal axis of furnace 2 at substantially less than a right angle in relation to the longitudinal axis of rotating drum 1 is composed primarily of individual filaments in comparatively spaced relation formed with only a few fibers composed of a plurality of monofilaments which result when several monofilaments adhere to each other after being attenuated from furnace 2 in contiguous relation. The portion of the rnat formed with the longitudinal axis of furnace 2 at an increased angle relation to the longitudinal axis of drum 1 is composed primarily of strands of monofilaments formed when the filaments are attenuated in contiguous relation and adhere to each other when wound on drum 1. If the mat thus formed is expanded after it has been cut along the longitudinal axis of the drum and removed therefrom by drawing it from one of its edges transverse the line of cut, the density of the resulting expanded mat is high in the portion formed when the furnace was disposed at substantially less than a right angle because of the great number of individual monofilaments in this portion of the mat. The density of the mat is lower in the portion formed when the longitudinal axis of the furnace was disposed at increased angular relation to the longitudinal axis of the drum because fibers are grouped into strands. It will be realized by one skilled in the art that a corresponding mat with similar characteristics could be formed by reversing the sequence of steps above outlined. Likewise, the formation of a condensed filamentous mat having continuously varying fiber density through the thickness of the mat can be accomplished by starting the formation of the mat with the longitudinal axis of furnace 2 at a preselected angle with respect to the longitudinal axis of drum. 1 and continually increasing the angular relation between the longitudinal axis of furnace 2 with respect to the longitudinal axis of drum 1 at a predetermined rate of movement. The initially formed portion of said mat will be composed primarily of monofilaents, but as the angular displacement increases, the monofilaments will fall one on the other in increasing numbers and therefore increase the total number of fibers which are grouped.

It is to be understood that for the purposes of this invention the longitudinal axis of the furnace can be correlated to the longitudinal axis as determined by a row of holes in the orifice plate. It further is to be understood that the aforedescribed inventive features of varying the traversing speed of the feeder means, of varying the angular displacement of the furnace relative the drum and of inrceasing the traversing speed in the reversal areas can be selectively combined in the manufacturing process of filamentous mat in accordance with the results desired for the final product.

The invention claimed is:

1. A method of making a condensed fibrous mat of a plurality of layers of fibers comprising: transversely reciprocating filament feeder means at a selected traversing speed in spaced relation from and axially along a drum; rotating said drum a multiplicity of times during each traverse of said feeder means; feeding a plurality of filaments from a multiplicity of spaced orifices in the bottom of said feeder means to said drum during successive traverses so filaments wound on said drum in one revolution of said drum overlap a portion of said filaments wound on said drum during the previous revolution of such feeder means to build up a corresponding succession of layers of filaments with each layer containing a multiplicity of helical turns extending continuously through the central area from one end reversal area to the other; pivoting said filament feeder means about an axis extending through the plane of said bottom wall to more than one position during the formation of said fibrous mats to vary the distance between adjacent filaments wound on said rotating drum.

2. A method for making a fibrous mat of a plurality of layers of filaments comprising: transversely reciprocating filament feeder means at a selected traversing speed in spaced relation from and axially along a drum; rotating said drum a multiplicity of times during each traverse of said feeder means; feeding a plurality of filaments from a multiplicity of spaced orifices in a bottom of said feeder means to said drum during successive traverses of said feeder means so filaments wound on said drum in one revolution of said drum overlap a portion of said filaments wound on said drum during the previous revolution to build up a corresponding succession of layers with each layer containing a multiplicity of helical turns extending continuously through the central area from one end reversal area to the other; forming a portion of said mat wherein said feeder means is in one angular position relative to an axis extending through the plane of said feeder bottom wall and forming a second portion of filamentous mat wherein said feeder means is at a second angular position relative to said axis extending through said bottom wall to vary the distance between adjacent filaments wound on said rotating drum wherein the difference between said first angular position and said second angular position is between 0 and 3. Method for making a fibrous mat of a plurality of layers comprising: transversely reciprocating filament feeder means at a selected traversing speed axially along a rotating drum, feeding a plurality of filaments from a multiplicity of spaced orifices in a bottom wall of said feeder means to said drum during the successive traverses of said feeder to build up a corresponding succession of :layers of filaments so filaments wound on said drum during one revolution overlap a portion of the filaments wound on said drum during a previous revolution to form filament layers containing a multiplicity of overlapping helical turns extending continuously through the central areas of said drum from one end reversal area to the other; and, continuously pivoting said filament feeder means about an axis extending through the plane of said bottom wall to continuously vary the spacing between adjacent filaments deposited on said rotating drum.

4. Apparatus for forming a filamentous mat comprising: a rotating drum; filament feeder means having filament feeding orifices in a bottom wall thereof and movably mounted for successive reciprocatory traverses along tracks disposed above a downturning edge of said drum to feed filaments from said filament feeder means to said rotating drum; filament feeder drive means for driving said filament feeder means in said traverse along said path; means for varying the speed of said feeder drive means to correspondingly vary the traversing speed of said filament feeder means; feeder pivot means to selectively pivot said feeder means about an axis extending through said bottom Wall.

5. Apparatus for forming a filamentous mat comprising: a rotatable drum; track means disposed along an edge of said rotating drum; carriage means mounted for movement along said tracks; filament feeder means having orifices in a bottom wall thereof to feed filaments from said carriage means to said rotating drum, said feeder means being mounted on said carriage means for reciprocatory motion through successive traverses along said downturning edge of said drum to feed filaments to said rotating drum; filament feeder drive means including endless belt means mounted for travel around spaced wheel means selectively disposed along the Width of said downturning edge of said rotating drum means drivingly connected to said filament feeder means to drive said feeder means back and forth along said downturning edge in response to movement of said endless belt means in one rotational direction; and, means for increasing the speed of said feeder drive means during the portion of the reciprocatory traverse of said feeder when said filament feeder means is in the end reversal area of a traverse and for decreasing the traversing speed of said feeder drive means when said filament feeder means leaves said end reversal area.

References Cited UNITED STATES PATENTS 2,798,531 7/1957 Jackson 156174 XR 2,913,037 11/1959 Modigliani 156-425 XR 3,029,649 4/ 1962 Steyh 7437 3,051,602 8/1962 Schairbaum 156-167 XR EARL M. BERGERT, Primary Examiner M. E. MCCAMISH, Assistant Examiner US. 01. X.R. 156-169, 425

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