US2902746A - Apparatus for producing needled batts - Google Patents

Description

Sept. 8, 1959 A. w. BATEMAN APPARATUS FOR PRODUCING NEEDLED BATTS Filed Oct. 10, 1956 2 Sheets-Sheet 1 INVENTOR ALVA WAYNE BATEMAN Sept. 8, 1959 A. w. BATEMAN 2,902,746

I APPARATUS FOR PRODUCING NEEDLED BATTS Filed Oct. 10, 1956 2 Sheets-Sheet 2 BY W AGENT United States Patent 2,902,746 I APPARATUS FOR PRODUCING NEEDLEDBATTS Alva Wayne Bateman, Newburgh, N-Y., assignor to I. du Pont de Nemours and Company, Wilmington, Del., a corporation of'Delaware Application October 10, 1956, Serial Nor 615,041 1 Claim. (c1. 28-4) This invention relates to unwoven fibrous materials and more particularly to'a'n' improved apparatus and process for needle punching unwoven fibrous batts, especially thin batts of slippery fibers.-

Needle looms have been used by the textile industry for many years in making punched felts from batts of carded or similarly oriented fibers such as hair, jute,- sisal and other natural fibers; These punched felts have been used, for example, as carpet linings, insulating felts, slicker felts and cartridge wadding. Recently, needle looms have beenused similarly in-making unwoven batts of synthetic fibers.

Basically, these needle looms consist: of a large number of closely spaced needles s upportedvin position to be reciprocated into then out of a batt of fibers and means, such as draw rolls and moving feed aprons, to pass the batt through the loom. The batt is usually moved intermittently through the loom, being advanced only while the needles are drawn clear of the batt. This needle piercing or punching orients individual or small groups of fibers substantially perpendicular to the plane of the batt, thereby giving added strength to the unwoven structure.

Although they have been satisfactory for punching batts of many natural fibers, conventional needle looms greatly distort batts of synthetic fibers which have a low coefficient of friction and slide easily over one another. This is especially true of thin batts of such materials as polytetrafluoroethylene which stretch and pull apart on conventional looms. With some thin batts, for example, those less than A inch thick, the unwoven fibrous structure distorts when it is suspended under its own weight over a short distance.

I have discovered an improvement in conventional needle looms which makes it possible to use such looms for punching thin batts of slippery fibers without greatly distorting the batts. This improvement comprises an endless flexible carrier belt for the fibrous batts which runs from the feed side of the needle loom to a point immediately adjacent to the punching area, passes outside the punching area to a point immediately adjacent to the discharge side of the punching area, and proceeds away from the loom.

The invention is described in detail hereinafter by reference to a preferred embodiment shown in the accompanying drawings wherein:

Figure l is a view in side elevation of the needle loom and carrier,

Figure 2 is a plan view of the needle loom and carrier,

Figure 3 is an enlarged cross-section of the bridge plates and punching area shown in Figure 1.

As shown in the drawings, the loom needles are held in the needle board 11 which, in turn, is fastened to the top beam 12. The needle assembly consisting of the needles 10, needle board 11 and top beam 12 is reciprocated substantially vertically between top-beam guides 13 by connecting rods 14 which are connected to drive shaft 15 through eccentric straps 18 and eccentrics 2 19. As the drive shaft 15 is turned by a prime mover through pulley- 16 and clutch 17, 'eccentrics' 19rotate within the eccentric straps 18 which move the connecting rods 14 and the needle assembly. As the needles 10 reciprocate, theypass downwardly through holes'in the stationary stripper plate 20, through the punchingv area I and finally through corresponding" holes in the; stationary bed plate 21. Figure L shows the position of the needles 10 as they begin their-downward stroke' Figure' il shows the needles after they have passed through stripper plate 20, the punching area andbe'd-plate 21.

In Figure 1, feed crank 22, fastened to eccentric 19, is rotatably connected to clutch lever ".23 which is also rotatably connected to clutch pitman 24 7 When the drive shaft 15 and eccentric 19' turn, clutch lever 23 causes clutch pitman 24 to oscillateback and forth. Ratchet 25 attached to clutch pitmanl 24 engages gear 26 and inter mittently rotates rear 'dr'aw'roll 27. The rear draw'roll 27 intermittently rotates forward draw roll 28 through chain drive 29; The slatted'feed apron 30is driven intermittently by frictional contact-With forward draw roll 28. Thus' the needle assembly, the -feed-mechanism and the rear draw roll 27 are all driven-from eccentric 19.

The'endless fl'exible' carrier: 31 runs along the top-surface of the slatted feed apron 30- up :to a point immediately. adjacent-to the-punching area. .FOI'WEIIds. bridge plate 32 is inserted inthespace betweenathe -feed end 1 ofbed plate 211and-;draw-roll 28' sotthat' the carrier'31 is supported between thefeed-apron 30 and the bed'plate 21. From the feed apron 30, the carrier 31 passes over the bridge plate 32 and downwardly through the small space between the bridge plate 32 and the bed plate 21. The carrier then runs around lower girts 33, thus avoiding drive shaft 15, and passes upwardly through the slit between the discharge end of bed plate 21 and a second bridge plate 34 which, like forward bridge plate 32, spans the gap between the bed plate 21 and the rear draw roll 27.

From this point immediately adjacent to the discharge side of the punching area, the carrier 31 goes successively between draw roll 27 and riding roll 35, under windup roll 36, over roll 37, under roll 38 and around pull roll 39 and guide roll 40 back to roll 41 at the end of the slatted feed apron 30. Roll 38 controls the tension in the carrier 31; by lowering this roll the tension is increased. Means are provided to synchronize the intermittent rotation of windup roll 36 and pull roll 39, with that of draw rolls 27 and 28.

The carrier 31 is driven by frictional contact with rear draw roll 27 and pull roll 39. The carrier 31 can be made of any of a wide variety of fabrics and sheetings, natural or synthetic, that is flexible enough to be threaded through the loom; however, coated fibrous sheets and polymeric films, for example, drill lightly coated with plasticized polyvinyl chloride and polyester film such as 350-A gauge polyethylene terephthalate sheeting, are preferred.

In operation, a loose unwoven batt 42 of fibers to be needle punched is laid on the carrier 31 on the feed apron 30 and is borne up to bed plate 21. As the batt 42 passes into the punching area between bed plate 21 and stripper plate 20, it is punched by the reciprocating needles 10 which orient small groups of fibers substantially perpendicular to the plane of the batt. Stationary plates 20 and 21 limit the verticle movements of batt 42 while it is punched and prevent it from reciprocating unduly with the needles. When the punched batt 42 has passed through the loom it again meets the carrier 31 where the carrier comes upwardly between the discharge end of the bed plate 21 and the bridge plate 34. From this point immediately adjacent to the discharge utility of the invention and is not intended to limit the inventionin any Way. 4

Example j Aloose batt of 4 /-inch, '6%-denier polytetrafluoroethylene fibers drawn t'entimes their extruded length was formed by cross-lapping from 13 to 15 layers of loose fibers. Thelo'osebatt was then fed to a needle loom equipped with a carrier of drill lightly coated with polyvinyl chloride. The carrier was. threaded over the bridge plates and through the loom fas shown in Figures 1, 2, and 3. The loom needles were 15 x 18 x 36 gauge, 3 /2 inches long, and close barbed andshallow barbed. I 'In 18 passes through the loom, the batt was punched 3868 times per square inch; The resulting product Weighted 17.6 ounces per square yard and was i -inch thick. During the needle punching the. batt stretched less than 15% in length and shrunk less than, 10% in width; similar battsof polytetrafiuoroethylene distort as I claim:

In a needle loom for punching unwoven fibrous batts which loom comprises a plurality of closely spaced needles, means to reciprocate said needles into and out of said batts, means for limiting the vertical movement of said batts as said needles pass therethrough, a feed apron, means to move said batts away from said loom comprising a draw roll, and a windup roll, the improvement which comprises a first bridge plate extending from the discharge end of said feed apron to a point on the feed side of said loom immediately adjacent to the area wherein said needles punch said batts, a second bridge plateextending from a point on the discharge side of said loom immediately adjacent to said area wherein said needles punch said batts to said draw roll, an endless, flexible carrier belt which runs along and in contact with the upper side of said feed apron, over the upper surface of said first bridge plate, downwardly over the edge of said first bridge plate immediately adjacent to said area where said needles punch said batts, outside said needles and said limiting means, upwardly over the edge of said second bridge plate immediately adjacent to said area wherein said needles punch said batts, over the upper surface of said second bridgeplate and over said draw roll to said windup roll, and means to control the tension in said endless,flexible carrier belt. 1

References Cited in the file of this patent UNITED STATES PATENTS Shaw -4; Jan. 17, 1956

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