US3058169A

US3058169A - Method and apparatus of forming batts and pads

Info

Publication number: US3058169A
Application number: US598129A
Authority: US
Inventors: Joa Curt George
Original assignee: Falls Paper and Power Co
Current assignee: Falls Paper and Power Co
Priority date: 1956-07-16
Filing date: 1956-07-16
Publication date: 1962-10-16
Anticipated expiration: 1979-10-16

Description

C. G. JOA

Oct. 16, 1962 METHOD AND APPARATUS OF FORMING BATTS AND PADS Filed July 16, 1956 2 Sheets-Sheet 1 mms/rox. der 6. Jaa BY QM JM r nf-LZ1 ArroRq/sv Oct. 16, 1962 c. G. JoA

METHOD AND APPARATUS OF FORMING BATTS AND PADS Filed July 16, 1956 2 R. n t mw m n m 0 Y m Wd 4m n A e Gn,... .x T 2 Nm. Hnmdnnhkh unrlldnllllhnnwnv. .m AN Q Cv. B A N W1 W MY United states Patent' o 3,058,169 METHOD AND APPARATUS F FORMING BA'I'IS AND PADS Curt' George Joa, Boynton Beach, Fla., assignor to Falls Paper 81 Power Company, Chester, Pa., a corporation of Wisconsin Filed July 16, 1956, Ser. No. 598,129 7 Claims. (Cl. 19144.5)

This invention relates to a method and apparatus of forming batts and pads and further relates to the resulting pad.

The batt is made by pneumatic projection of batt forming material such as wood pulp into a throat defined by progressively convergent top and bottom belts and relatively xed side walls. In the past, it has generally been the practice to permit the air of the convection current to escape through the confining belts, these being made of screen cloth or otherwise made foraminous for this purpose. I havediscovered that superior results are possible in the way of making a batt of more uniform density if the air is withdrawn from the forming throat at its entrance, a withdrawal chamber being provided across which the batt forming material is projected at sufficiently high velocity so that its momentum packs it between the belts, precluding it from being entrained to any substantial extent in the escaping air of the convection current.

To accomplish this result, the withdrawal chamber is made of relatively large capacity and a nozzle enters this chamber and is directed across a substantial space toward the forming throat. Desirably, but not necessarily, the convection current is not released into the withdrawal chamber until it, and the entrained batt forming material, has partially traversed the chamber.

Since the material may be packed at considerable den 3,058,169 Patented Oct. 16, 1962 t.. ICC

that multi-ply pads can be cut therefrom, the convexity of each batt in cross section being cumulative in the finished batt and in any pads severed therefrom by a transverse cut.

In the drawings:

FIG.1 is a view in side elevation of apparatus embodying the invention.

FIG. 2 is a view in longitudinal section through the apparatus oi FIG. l.

FIG. 3 is an enlarged detail view taken in cross section on the line 3--3 of FIG. 2.

sity and under substantial pressure between the throatforming conveyors which constitute the top and bottom of the chamber, these conveyors, which usually comprise belts of leather or canvas, are provided with backing supports to prevent them from being deformed.

Assuming that the batts are to be cut into pads such as those usable in sanitary napkins, it is possible and desirable to provide backing supports for one of the conveyors of the throat which are more widely spaced at the center of the conveyor than adjacent its margins so that the resulting batt has maximum thickness at its center and tapers toward its edges. A wide variety of batt contours, in cross section, is achievable in this manner. When the desired pads are then severed from the batt by cutting the batt transversely, it will be found that each pad will have a contour in lengthwise section which is identical with the lateral contour of the batt. In the de sired construction illustrated, the pad will taper uniformly to both of its ends.

I am aware that pads have heretofore been made which have tapered to their ends but the prior art pads with which I have been familiar have been tapered by pressure with the result that they are more dense at their ends than at their centers. Since it is one of the objectives and results of the mechanism and method of batt formation as herein described to produce a batt which is of uniform density throughout, it will be obvious that by controlling the cross section of the batt and cutting the pads transversely therefrom, I am able for the first time to produce a pad having non-parallel top and bottom surfaces and in which the lack of parallelism is achieved without density variation, each pad being homogeneous and of uniform density throughout regardless of its contour.

In one embodiment hereof, I have shown an arrangement whereby batts constructed as herein disclosed may be laminated with webs of paper or other materials so FIG. 4 is an enlarged detail view in cross section taken on the line 4-4 of FIG. 2.

FIG. 5 is a fragmentary view in perspective showing the manner in which successive pads are cut from a batt made in accordance with this invention.

FIG. 6 is a view in transverse section through a batt forming chamber representing a modified embodiment of the invention. p

FIG. 7 is a diagrammatic view in longitudinal section showing means for forming a plurality of batts in accordance with the invention and for laminating these with each other and with paper webs.

FIG. 8 is an enlarged detail view fragmentarily illustrating in transverse section a laminated batt produced according to FIG. 7.

FIG. 9 is a view in perspective showing a multi-ply pad having its component plies made in forming chambers of the transverse section shown in FIG. 6.

Apparatus for delivering batt forming material to a convection current is well known. Therefore, it is illustrated only diagrammatically herein. One type of apparatus suitable for use with the present invention is illustrated in U.S. Patent No. 2,618,816.

In the present diagrammatic drawings, blower 5 fed with air through pipe 6 and with pulp through hopper 7 discharges the convection air and entrained pulp through pipe 10 to nozzle 11. The material entrained in the convection current is projected from the nozzle at high velocity into a throat l2 formed by an upper conveyor 13, a

-lower conveyor 14 and side walls 15 and 16, the latter being best illustrated in FIG. 4.

The belt 14 which provides the bottom of the forming throat extends about a pulley 17 which is located behind nozzle 1l as best shown in FIG. 2. The upper belt 13 is guided about a shcave 18which is located forwardly of the nozzle. An escape chamber 19 for convection gases encloses a portion of the nozzle and all the space between the

belts

13 and 14 in the manner best shown in FIG. 2. From this chamber a return pipe 20 for convection gases I eads back .to the device in which the batt forming material is entrained in such gases, the air being largely recirculated. Thus, any material which passes with the return air from an escape chamber 19 is simply recirculated and commingled with newly arriving batt forming material.

The upper and

lower belts

13 and 14 are confined between

guide members

21 and 22 of any appropriate shape in cross section. For special purposes above alluded to, these guide members may be closer together adjacent the sides of

conveyors

13 and 14 than at the center of the forming throat. This gives a cross section between the conveyors which has a maximum thickness at the center and tapers toward both sides as best shown in FIG. 6. The resulting batt 25 is formed with the same cross section, whatever that may be. Accordingly, when sanitary napkins or other pads 26 are severed from the batt by a transverse cut, these will taper toward both ends as indicated in FIG. 5r in which the dotted line 27 is the line of the cut. Assuming that it may be desired that the pad have rounded corners, the batt -may be preliminarily notched at 28 in line with the cut 27.

At the delivery end of the forming throat, the pulleys 29 and 30 for the upper and lower belts \13 and 14 may be slightly closer together than the pulleys 18 and 17, the supports 21 and 22 for the conveyors being likewise convergent. This results in subjecting the batt to progres. sively increasing pressure as it passes through the throat. The amount of convergence wil1"determine the extent to which the batt will be compressed. However, all portions of the batt will be of substantially identical density since the high velocity of the batt forming material as it issues from the nozzle 11 determines the initial density, this being uniform throughout the cross section of the throat. Since the batt is of uniform density initially, and is uniformly compressed, all portions of the batt issuing from the device will likewise be uniform in density.

If desired, two -or more batts may be laminated with each other and with other plies to make a composite batt.I FIG. 7 shows two batt forming devices identical with those described, each including a throat 11 projecting through a gas escape chamber 19 to project batt forming material -at high velocity into a throat 12 which comprises an upper conveyor 13 and a lower conveyor 14, both of which, as in the previous device, operate convergently toward the point of discharge.

At the discharge point, the upper batt 25 passes onto a web 32 from supply roll 33. This web may be of suitable material. As an example, it may comprise a moisture distributing ply of lm or impregnated tissue to constitute the center ply of a known type of sanitary napkin pad. The web 32 is supported on a conveyor 34 and ultimately it is laminated with another web 35 from supply roll 36. This web may comprise absorbent tissue paper, but for other purposes other materials may be used.

The batt 250 from the lower apparatus is received onto a conveyor 38 which leads it onto a web 320 fed from a supply roll 330 and supported on conveyor 340. In the assumed example, the web 320 may comprise tissue with or without impregnation. As the web 320 leaves conveyor 340 and passes onto conveyor 40, it is joined by the web 32 fed downwardly on conveyor 41 and having the pulp batt 25 and the cover web 35 already laminated therewith. FIG. 8 shows the various component laminations.

Assuming that the throats 12 illustrated in FIG. 7 have cross sections which taper laterally as in FIG. 6, the sanitary napkins 260 cut therefrom will cumulate the convexity of the respective batts in the manner shown in FIG. 9.

I claim:

1. A method of continuous batt formation which comprises pneumatically projecting in a gaseous convection current batt forming material at high velocity from a nozzle spaced from a relatively stationary forming throat into said forming throat, advancing the deposited batt forming material through the relatively stationary throat and separating said material from said gaseous current by withdrawing gas of the convection current before it reaches said throat and in a direction transverse to the path of projected batt material, the batt forming material being projected by its own momentum across the path of the transversely escaping convection gases.

2. The method recited in claim 1 including the further step of progressively compressing the batt forming material as it passes through the throat.

3. The method of claim 1 which includes packing a greater amount of batt forming material along the center line of the throat than along the margin thereof, tapering said batt forming material from said center line to said margin, packing all such material at substantially uniform density, and thereafter transversely severing the resulting batt transversely to provide pads of uniform the margins of the batt.

4. A method of making pads each of which tapers in thickness to one end, which method comprises forming an elongated batt by projecting batt forming material into a throat shaped to provide a transverse taper to one margin of the batt corresponding to `the longitudinal taper desired in the pad, depositing the material in the throat with substantially uniform density throughout the cross section of the throat, advancing the batt through and clear of the throat as the batt is formed, and subsequently transversely cutting the batt at spaced intervals to provide severed pads of substantially uniform density but tapering in thickness.

5. A continuous batt forming apparatus comprising the combination with spaced conveyor means and confining walls constituting a batt forming throat having inlet and discharge ends, a nozzle for carrying batt forming material in convection gases, said nozzle being directed toward the inlet end of said throat and spaced therefrom to permit separation of convection gas from said batt forming material in said space and to provide for the escape of convection gases before such gases reach said throat, and means for supplying convection gases and entrained batt forming material through said nozzle at high velocity to traverse the space between the nozzle and the throat, the convection material being projected by its own momentum across the path of gases escaping from the throat.

6. A continuous batt forming machine comprising spaced conveyor aprons and lateral confining members defining a throat having inlet and discharge portions, means for operating said conveyor apron along the throat from its inlet portion toward its discharge portion, a convection current nozzle spaced from at least one of said aprons and from the inlet portion of the throat for projecting a stream of gas and entrained batt forming material at high velocity toward the inlet portion of the throat, and means for separating gas from said stream comprising a gas withdrawal chamber between said nozzle and throat and means for inducing discharge of said gas through said chamber in a direction transverse to the direction of travel of said batt forming material.

7. In a device of the character described, the combination with a convection conveyor nozzle of a forming throat comprising a tirst conveyor originating behind the nozzle and extending in the direction of projection of the nozzle, a second conveyor disposed in spaced facing relationship with the first conveyor and having an end located forwardly of the nozzle in the direction of projection from the nozzle, longitudinally extending closures between these conveyors, means for operating the conveyors in a direction away from the nozzle, and a gas separating chamber above the trst conveyor and extending to the second conveyor and into which the nozzle extends, the noule comprising means for directing convection gas and entrained batt forming material at high velocity across the separating chamber in which the convection gases are separated from the batt material by escaping through said chamber before the batt material reaches the throat.

References Cited in the file of this patent UNITED STATES PATENTS 735,217 De Long Aug. 4, 1903 1,468,028 Maussner et al Sept. 18, 1923 1,756,468 Moller Apr. 29, 1930 1,794,358 Bauer Mar. 3, 1931 1,869,177 Thompson July T26, 1932 1,974,578 Medol Sept. 25, 1934 2,086,757 Williams July 13, 1937 2,195,158 Watts Mar. 26, 1940 2,325,265 Millar July 27, 1943 2,479,911 Delloye Aug. 23, 1949 2,618,816 Joa Nov. 25, 1952 2,715,755 Jones Aug. 23, 1955 I2,721,554 Joa Oct. 25, 1955