Nova Patents
US2699208A

Apparatus for forming perforated tea bag paper

Abstract

This record has no abstract on file.

US2699208A, drawing sheet 1
Sheet 1 of 11

Term

Term ended

Expired 11 January 1972, 54.7 years ago.

  1. Priority and filed
  2. Granted
  3. Expired
  4. Today

6 claims: 6 independent, 0 dependent

  1. 1
    I claim:1. A perforating apparatus for tea bag paper comprising a rubber covered backing roll, a perforating roll, tion to said perforating roll, and means for training and drawing a continuous web of said tea bag paper through the nip formed by said perforating roll and. opposed backing roll, said perforating roll havmg solid densitv^of at least about 500 teeth per square inch, and said teeth having substantially flat outer faces the edges of which form cutting edges and being rectangular m cross section and of uniform cross section from the outer 70 face to the root thereof with a lennth from outer fae to root sufficient for perforating said web. whereby said, teeth act against said rubber backing roll, to runture nerforations with a corresponding densitv in said tea bag suae- Paper and the uniform cross section of said teeth results inch and 75 in forming said perforations consistently in a size corresponding with the size- of. said teeth independently of anv variations in the weighting of said backing roll.
  2. 2
    A perforating anparatus for tea bag naner as defined in claim 1 and further characterized in that an air moving device is disnosed for acting on said web hevond the nro of said perforating roll and onnosed. bacxinv roll to remove flap portions adhering at the perforation ruptures and for cleaning said web.
  3. 3
    A perforating anparatus for tea bag paper as de10 cator or doctor blade 20 against which the paper web 12 runs. The tissue sheet forming the web 12 may be made heat-sealable, in accordance with, the disclosure of _my prior application, by a coating of vinyl resin, such as vinyl butyral. This coating may be applied in restricted areas, if desired, to correspond only with the locations at which the web 12 is finally to be heat sealed in forming tea bags therefrom, but usually it will be more convenient to make an overall coating application of the vinyl resm in an amount of about 15% to 20% based on the dry weight of the coated paper. Beyond the coating station 16, the web 12 may be suitably trained beneath a source of infrared heat, as at 22, and then over a heated drying drum 24, to dry the resin coating. . From the drying drum 24, the web 12 is passed downwardly under a guide roll 26 and then through the nip formed by a perforating roll 28 formed in accordance with the present invention, and a rubber covered backing roll 30 which is adjustably weighted in opposed relation to the perforating roll 28 by suitable means as indicated by the reference numeral 32. The perforated web 12 may then be passed over a spreader bar as at 34, over a reversely driven brush roll as indicated at 36 for removing flap portions adhering at the ruptured perforations, past a stationary brush and associated suction means as illustrated at 38 for further removal of flap portions and cleaning of the web 12, under a further spreading device as at 40, and finally rewound in roll form at 42. ,. The form, of perforating roll 28 employed according to the present invention is illustrated further in Fig. 2 of the drawing in which the peripherally toothed body of the roll as at 44 is shown mounted on a mandrel 46 between retaining collars 48 and jam nuts 50 (compare Fig.. 5). The body 44 of the perforating roll 28 could, if desired, be made as a solid unit, but it is preferably formed, m accordance with the present invention of an alternating series of toothed discs 52 (see Fig. 3) and intermediate spacing discs 54 (see Fig. 4), the diameter of the spacing discs 54 being not greater than the root diameter of the teeth 56 formed at the periphery of the discs 52. The teeth 56 in the discs 52 may be machined after the alternating series of discs 52 and 54 have been placed on the mandrel 46, as illustrated in Fig. 5, and locked m „„ ------ ... .„ . place between the retaining collars 48 and jam nuts 50, 45 after which it will be noted the sheet is substantially by cutting or milling spaced grooves parallel to the man- =----= --- --- --drel axis in the peripheral surface of the result m roll body 44. Usually, however, the teeth 56 may be formed with greater facility and to better advantage by stamping - - --,.. or die cutting them in the individual discs 52 beforehand^ gg tjon gerjaj No. 448,608, filed August 9, 1954, which in which case they may be assembled on the mandrel 46 ..... - ·------' — without any attempt to align the teeth 56 of the individual discs 52. ...,, In forming the perforating roll 28 m this manner, the ayplllvauun uac> „„„ toothed discs 52 may suitably be cut from shive stock or 55 aforesaid copending about 0.007 thickness, with teeth 56 having a width ot .about 0.011, and with a spacing of at least comparable width provided between the teeth 56. The spacing discs 54 may in turn be formed from a material such as spring a 1UUto - ,— -....... —, steel having a thickness at least about as great as the spac- 60 m“ans for wejghting said backing roll in opposed relaing provided on the discs 52 between the teeth 56. this -- -..... --- ----- --=-=arrangement makes it possible to provide easily a very high density of teeth 56 on the peripheral surface of the perforating roll 28, and thereby obtain the large number υα.^.„Ά ,------------------ --. ... .-of tiny ruptured openings m the tea bag paper necessary 6g space(j on the perinheral surface thereof with a. for providing a satisfactory extraction rate. . - -- ---------- =---In order to provide an extraction rate which is acceptable in tea bag paper, I have found that the teeth 56 should be formed with a density of at least 500 teeth per square inch, with each tooth of a size such, that the corresponding number of perforations ruptured in the paper will form an open area of at least 5 per cent of .its total area (excluding unperforated heat-sealing margins, of course). A perforating roll 28 formed with toothed discs 52 and spacing discs 54 in the dimensions noted above results in spacing the teeth 56 with a density of 837 per square meh ?.n<i provides a corresponding density of ruptured perforations in the tea bag paper forming an open area of 7.0 per cent of its total area. . .Fig. 6 of the drawings shows a modified, arrangement ot a perforating roll of the type just described above that is adapted for large-scale production by means of a plurality of roll bodies 58 for forming multiple strips of tea bag paper simultaneously. The roll bodies 58 are formed 2,699,208 cross sectional dimension of said teeth is at least about 50 per cent greater in a direction circumferentially of said roll than longitudinally thereof.
  4. 4
    A perforating apparatus for tea bag paper as deiined m claim 1 and further characterized in that means are disposed beyond the nip of said perforating roll and opposed backing roll for brushing said web at the face thereof trained in contact with said backing roll.
  5. 5
    A perforating apparatus for tea bag paper as deimed m claim 1 and further characterized in that a gabardine covered brush roll is disposed to run in contact with said web beyond the nip of said perforating roll and opposed backing roll.
  6. 6
    6 A perforating apparatus for tea bag paper as deimed in claim 5 and further characterized in that a stationary brush and associated suction means is disposed to act on said web face beyond said gabardine covered roll for further removal of adhering flap portions and for cleaning said web. 714,667 845,764 927,846 1,466,001 1,574,633 1,668,084 1,818,046 1,912,495 1,931,468 2,009,288 2,201,481 2,218,674 2,261,315 2,316,054 2,556,071 1,621,741 References Cited in the file of this patent UNITED STATES PATENTS Carlton______________ Curtis____________ Flett________________ Metzner_____________ Myover______________ Oliver_______________ Pamphilis____________ Phelan______________ Bergholtz____________ Beckmann___________ Dollahite_____________ Eaton_______________ Thorsen_____________ Davis________________ Denton______________ Kane________________ FOREIGN PATENTS Germany--------------Nov. 10. 1883 _ Dec. 2, - Mar. 5, July 13, Aug. 28, Feb. 23, - May 1, Aug. 11, 1931 June 6, Oct. 17, July 23, May 21, Oct. 22, Nov. 4, - Apr. 6, . June 5, Dec. 16, 1902 1907 1909 1923 1926 1928 1933 1933 1935 1940 1940 1941 1943 1951 1952 24,788
Independent claims6