US 3475252 A
Description (OCR text may contain errors)
Oct. 28, 1939 o. D. WHITE 3,475,252
STRUCTURAL HQNEYCOMB MATERIAL Filed Nov. 2?, 19'64 United States Patent 3,475,252 STRUCTURAL HONEYCOMB MATERIAL Desmond Deverell White, Radlett, England, assignor to Dufaylite Developments Limited, a British company Filed Nov. 27, 1964, Ser. No. 414,065
. Int. Cl. B26d 5/08; B321) 31/00 US. Cl. 156-353 2 Claims ABSTRACT OF THE DISCLOSURE US. Patent No. 3,166,456 of White, Thwaites and Judd describes apparatus for making structural honeycomb material in which a web of sheet material is formed with equally spaced transverse rows of colinear slits, which slits leave therebetween portions of intact material which act as hinge formations. The thus perforated web is fed downwardly onto a support where it folds automatically concertina fashion. Between being perforated and reaching the support the Web has applied to both sides thereof longitudinally extending bands of adhesive, the bands on one side of the web being staggered with respect to the bands on the opposite side thereof. Thus, in the concertina folded material the glue bands are in the correct position for the manufacture of structural honeycomb material. Excellent results have been obtained in this manner. a
The present invention is concerned with the apparatus for producing the rows of transverse slits. In the apparatus the web passes around the periphery of a rotating drum, and the drum is provided with a toothed retractable blade. Means, for example pneumatic rams, are provided on the drum for forcing out the blade so that the teeth project from the periphery of the drum in a stabbing motion. Each tooth penetrates the paper and forms one of the slits.
Prior methods of forming slits in the travelling web have involved the use of rotating drums carrying fixed blades which press the paper on to another drum-see for example US. Patent No. 3,166,456 of D. D. White (the present applicant) et al. A fixed blade is found to give unreliable results and even to fail frequently in its operation. In contrast the blade of the present invention with its stabbing action functions. reliably and effectively.
The present invention relates to the production of structural honeycomb material and has as an object the provision of improved apparatus and methods therefor.
In the Patent No. 3,166,456 of Desmond Deverell White, Peter John Thwaites and Geoffrey Ronald Judd there is described a method for the production of structural honeycomb material which comprises applying wet bands of adhesive to both faces of a web of bibulous sheet material in positions such that the bands applied to one face are staggered with reference to the bands applied to the other face, feeding the web downwardly towards a support and folding it backwards and forwards upon the support so that it is accumulated upon the support in the form of a stack of layers which are adhered together by the wet hands and are interconnected at their ends, characterised in that the web is formed at equidistant intervals along its length and thereby divided into discrete sheet sections, with hinge formations, and is fed downwardly to the support at a rate of feed such that it swings freely backwards and forwards under the reaction of the support and is accumulated in the form of a stack of layers in which each layer is constituted by one of said sheets and the sheets are joined together by folds at the position of the hinge formations. There is also described apparatus for carrying out this method, which apparatus comprises means for forming a travelling web of bibulous sheet material at equidistant intervals along its length with hinge formations, adhesive applying means Patented Oct. 28, 1969 for applying wet bands of adhesive to both of the faces of the travelling web in positions such that the bands applied on one face are staggered with reference to the bands applied to the other face, and a support positioned to receive the web bearing the wet adhesive whilst the web swings freely over and descends to the support. As shown in the said application the hinge formations are preferably sets of colinear transverse slits which leave the sheets joined together by intervening sections of intact material.
In accordance with the present invention there is provided an improvement in or modification of the said apparatus in which there is provided a device for perforating the web material to form the sets of colinear transverse slits, which device comprises a roller carrying at least one perforating tool mounted to be driven between a retracted position and a position in which it projects from the peripheral face of the roller whilst the roller is being rotated.
In the application of the device, the web material is moved over the roller in such a manner that it is supported in rolling contact over a substantial area, the perforating tool being driven between its retracted and projecting positions to perforate the material whilst it is supported in this way. As the tool and the web move together with the roller and at the same speed, the perforating operation is achieved without interrupting the motion of the web. This is advantageous not only because the need to provide complex feeding arrangements is avoided but also because the smooth continuous motion of the web avoids jerking the perforated material and so allows such forms of perforation as divide the material into weakly interconnected sections to be provided in a reliable manner.
In a preferred arrangement the tool is driven by fluid operated, preferably pneumatic, actuators carried by the roller. Such actuators are readily arranged to produce a rapid stabbing motion of the tool which is found to be beneficial in that it minimises the tendency of the web material to be pushed away from the former. A cam induced motion for the tool tends to consume considerable power when arranged to give a stabbing action.
The device is found to be capable of providing perforations in a remarkably accurately positioned manner provided that precautions are taken to prevent slipping of the web material at the face of the former. In one convenient and very simple arrangement for this purpose the roller is provided with a pair of pinch rollers preferably faced with rubber or other flexible material for holding the web in contact therewith. It is found that by driving the second pinch roller, that is the roller at which the web leaves the roller, and allowing the first pinch roller to idle a satisfactory drive for the drum is obtained; moreover the arrangement will readily draw the web material from an undriven or even braked supply roll, no take-off rollers being required. The accuracy of performance of the apparatus is found to be improved if the perforated material is maintained under light tension after leaving the former. I
In order to illustrate the invention there is given the following description of a preferred embodiment of the perforating device installed on a machine for the manufacture of structural honeycomb material. In the said description reference is made to the accompanying drawing in which:
FIGURE 1 is a perspective drawing showing the perforating device and the printing rollers of the machine,
FIGURE 2 is a cross section taken on IIII of FIG- URE 1,
FIGURE 3 shows a part of the perforating tool, and
FIGURE 4 is a diagrammatic drawing which shows the manner in which the perforated and printed web is formed into honeycomb material.
In the perforating device shown in FIGURE 1 a drum 1 is formed with a longitudinal radial slot 3 along its whole length. Any convenient construction may be employed and in the case illustrated the drum was formed by assembling a series of circular discs cut from wooden blockboard and machining the surface truly cylindrical. The grain pattern over the periphery of the drum gave a surface providing a useful amount of friction with rough surfaced paper when used as the web material. The axle 5 of the drum is hollow and is connected via a rotational pressure coupling with a source of compressed air (not shown). On each end of the drum is mounted a pneumatic ram one of which 7 is shown in FIGURE 1. The ram 7 is energized from the axle 5 via a valve 9, the plunger 11 of which is operated by a stationary cam 13. A similar valve and cam arrangement is provided for the ram at the other end of the drum. Carried by the rams within the slot 3 is a perforating tool 15 in the form of a plate profiled at its radially outermost side to provide a series of uniformly spaced triangular teeth 17.
In a modified arrangement giving improved mechanical symmetry, the tool is carried, at each end of the drum by a bridge member operated by a pair of rams.
For pressing the web material 19 into firm driven contact with the drum 1 there are provided a pair of rubber faced pinch rollers 21 and 23 operated by pneumatic rams 25. These rams force the pinch rollers into contact with the web material and also serve for holding them clear when threading the web material. Roller 21 is driven from an appropriate motor.
As the drum 1 rotates Web material is drawn from the supply roll 27 to pass without appreciable slip over the peripheral surface of the drum 1. During its passage be tween rollers 23 and 21 the tool 15 is pushed outwardly in a stabbing movement by its pneumatic rams under the action of the cams to provide a series of colinear slits 29 separated by short residual sections 31 of the material. The tool is retracted by the action of the cams before reaching the roller 21. If desired there may be provided an axle carrying a series of discs running in contact with the drum to support the portions 31 of the material during the stabbing action, but this complication has been found unnecessary for the manufacture of honeycomb material from stout paper.
conventionally arranged printing rollers 33 and 35 are positioned below the pinch roller 21 for the application of continuous bands of adhesive to opposite faces of the perforated material, those on one face being positioned between those on the opposite face. The adhesive bearing material on leaving the rollers descends to a support 37, FIGURE 4. Provided that the distance between the roller 35 and the support 37 is correctly chosen, the material swings to and fro under the reaction of the support, folding at the positions of the slits 29 to provide a block 39 of lightly adhered honeycomb which, after consolidation under pressure, may be cut into expandable slices.
The accuracy of perforating is such that a neat registration of folds is obtained at the ends of the block. The trimming waste of material is therefore trivial.
1. In an apparatus for the production of structural honeycomb material which comprises means for support.- ing a traveling web of bibulous sheet material, adhesive applying means for longitudinally applying wet bands of adhesive to both faces of the travelling web in positions such that the bands applied on one face are staggered with reference to the bands applied to the other face, support means positioned to receive the web bearing the wet adhesive while the web swings freely thereover and descends to the support, a device for perforating the traveling web to provide said travelling web with hinge formations in the form of sets of colinear transverse slits at equidistant longitudinal intervals so as to leave the material of the web between said slits intact, said device comprising a roller carrying at least one blade having a series of teeth for forming said slits, said blade being mounted to be driven between a retracted position and a position in which it projects from the peripheral face of the roller while the roller is being rotated and fluid operated actuators carried by the roller for driving the blade between said positions.
2. In an apparatus for the production of structural honeycomb material which comprises means for supporting a travelling web of bibulous sheet material, adhesive applying means for longitudinally applying wet hands of adhesive to both faces of the travelling web in positions such that the bands applied on one face are staggered with reference to the bands applied to the other face, support means positioned to receive the web bearing the wet adhesive while the web swings freely thereover and descends to the support, a device for perforating the travelling web to provide said travelling web with hinge formations in the form of sets of colinear transverse slits at equidistant longitudinal intervals so as to leave the material of the web between said slits intact, said device comprising a roller carrying at least one blade having a series of teeth for forming slits, said blade being mounted to be driven between a retracted position and a position in which it projects from the peripheral face of the roller while the roller is being rotated, actuators for driving the blade between said positions, an idling pinch roller for bringing the travelling web into contact with the blade carrying roller and a driven pinch roller for driving the web and the blade carrying roller, said driven pinch roller cooperating with the idling pinch roller to hold a section of the web in contact with the circumference of the blade carrying roller.
References Cited UNITED STATES PATENTS 1,704,186 3/1929 Gammeter l56-256 XR 1,988,640 1/1935 Welsford 156-253 XR 2,754,023 7/1956 Sheridan l56564 XR 3,159,518 12/1964 Benton 156510 XR 3,166,456 1/1965 White et al. l56197 HAROLD ANSHER, Primary Examiner J. C. GIL, Assistant Examiner U.S. Cl. X.R.