An atomic model in a single piece of injection-molded plastic is provided herein which represents the two electrons in co-valent electron bonding between atoms, and simultaneously represents the allosteric spin capability around an axis perpendicular to the centers of two conjoint co-valent electron faces on two atoms. This model includes a small cylindrical stud arising from a flat face cut into one (or up to four) curved surfaces or segment(s) of a physical three-dimensional spherical body which represents the electron available for donation by an atom. It also includes on each face a hole which is cut intaglio or dropped vertically into the face of the atom next to the raised stud. This hole is arced in a 90-degree arc about the contiguous electron-representing stud which arises above it like a nose above a smiling mouth. This arced slot represents the available space in the outer shell of the receiving atom into which a donated electron-stud from another atom may be inserted. The arc permits the two mutually opposed and inserted electron-representing studs to circumscribe arcs about each other when mutually inserted, and when twisted by the model maker's wrist action, achieving up to 180 degrees of spin about the axis circumscribed by two so-mutually alterably positioned electron-studs overagainst each other.

(1) Field of the Invention
The present invention relates to models used for representing atoms, (and when connected to each other, for representing molecules, also), and in particular to a novel and improved model of this type which represents electron pair-sharing and simultaneous allosterism or spin capacity about the axis established along the line of the covalent bond between the two shared electrons of the two conjoined atoms, this simultaneity being an otherwise difficult and hitherto unsolveable problem.
(2) Description of the Prior Art
Several patents have been established relating to molecular and atomic models.
(a) For example, U.S. Pat. No. 5,030,103, patented Jul. 9, 1991, by Buist, et al, is elaborate in the extreme, containing a large number of separate and motile parts, a large number of lobes and grooves, pins and rings, of raised and cut features; even wires 29 are required. It is therefore extremely complex to assemble, and costly to produce, whether in plastic, metal, a combination of these, or of any other medium. And it is confusingly called a molecular model. Beside that the inventor does not indicate what the verticle arcuate swing of the levers or arms are intended to represent in the real atomic world. Buist does state in his abstract that the assembly includes a three dimensional body representing an atomic core. Presumeably, he means an atom.
In contrast my small sphere simply represents an atom with flat faces cut onto it, one face for each electron-representing stud to donate or share, and a receiving slot for an electron-representing stud to be inserted into, one such face for hydrogen, two faces for oxygen, three faces for nitrogen, four faces for carbon. My model is a model of simplicity.
Buist however elaborates a "first cylindrical hole," longitudinally in the center of the central unit, which has no referent in the atomic or molecular world. No atom has a cylindrical hole so it is impossible to know what this represents. My model has no central longitudinal cylindrical hole, because the atom has no central longitudinal cylindrical hole, and nothing that acts like such a hole, either. I do make use of a small, simple cylindrical hole for a non-claimed function to represent what is known in chemistry as the "delta positive" capacity of some atoms. This hole is located on the rounded ends of some embodiments of my model: on the oxygen, hydrogen, and nitrogen embodiments, for receiving an electron-representing-stud as in hydrogen bonds, but I make no claim for this cylindrical hole.
Buist next elaborates "a plurality of connecting guiding elements, e.g., arcuate lobes project from". . . the body, and "a plurality of arcuate slots . . . inset into such three-dimensional body." The word "slots" here brings Buist's mode as close to my model presented herein as it ever comes. But the Buist slots are for axial arcuate pivoting of projecting arms. These separate arms are fitted into the slots by complicated groves, allowing vertical movement only, and seem capable of representing only the electron, but not the open space on the outer electron shell of the electron into which another electron may be inserted. In my model the slot represents only the available space in the outer electron shell into which a covalent electron may be represented as received. The wrist end of Buist's projecting arm or lobe is capable of either insertion or of reception. This feature is quite different from my model in which the stud, the male member, is the only member which represents an electron and can be inserted. And the slot is the only part of the model which will receive another stud, as the proper female member should. The word "slot" does not make my model and the Buist model the same or similar. Buist has a female end on the end of a male end.
Let us examine these stud and slot features of the Buist model closer to see whether Buist has already captured the ideas of electron-pair-sharing and of allosterism, and of reresenting these ideas simultaneously, and even more importantly of doing so as I propose to do in a novel way.
Buist does not actually disclose "a molecular model having a small cylindrical stud (113) which fits into an arched slot (112) of a representation of a carbon atom (110)." His stud (113) is not cylindrical except on one end; on the other end it is a rectangular cuboid called a "yoke" 115 (or 114) which forms the shoulder bone of the vertically arcing projecting arm, in both FIG. 12 and FIG. 13. (And this "stud" is sometimes male (113m) and sometimes female (113f).) This yoke or separate piece must be "compressed slightly to fit into the slot 112" and is further complicated by being split at one end into "two spaced apart legs 115a" allowing compression for insertion into the slot. And the small cylindrical stud does not fit into an arched slot, but into the yoke 114 (in one representation: FIG. 13). Buist even uses a separate flexible pin 117 to lock the split yoke onto a central cylinder.
And the fit of this separable hybrid cylinder-yoke into the arched slot in Buist is different from my model in two ways: first, his arch or arc follows the rounded contour of the outer body shape of the atom sphere vertically, whereas my arc is cut vertically into a flat face on the round atom sphere, not on the rounded contour of the atom-sphere. My arc circumscribes two contiguous electron-representing studs. As such, the deciding difference is that the Buist arc is intended to represent variable "internuclear distances which correspond," he says, to various carbon bonds between two atoms, whereas my model makes no such effort. My arc is intended to represent only the spin of two contiguous atoms about an axis perpendicular to their contiguous faces, but to accomplish this simultaneously with the sharing of two spatially separate stud-electrons. The Buist model is incapable of this achievement.
Very significantly, Buist's rotation or what I call allosterism or spin about an axis is achieved by what he calls "free rotation . . . allowed by the ring and groove connection" in the wrist of his hybrid cylinder-yoke arm, where the male pin 13m rotates inside of the female arm 13f, but rotates more or less depending upon the depth of the male wrist insertion into the female wrist. There is no trick to the Buist spin or rotation. It is the simple rotation of a round stud in a round hole. In my system two studs are permitted to rotate about each other|
One is at a loss as to what the verticle ar or slot in the atom-sphere body is intended or supposed to represent, or to accomplish in the Buist model, from his descriptions or from his drawings. Thus Buist cannot avoid the problem, as he admits, that some of his electrons must be represented as male and the others as female. In my model both electrons in a co-valent bond are represented by male studs, and both open positions in the outer electron shell of both conjoint atoms are epresented by female slots. And when conjoined these four elements, two sets of opposing studs and slots, each filling the other, accomplish both the ideas of electron pair-sharing and the capacity of allosterism simultaneously.
The mere fact that both models have pins or studs and slots does not make them the same, obviously. A "slot" by itself may represent anything or nothing (as Buist's verticle arc seems to have no function.) A slot may be one of a host of varying sorts of holes, with a variety of possible shapes and as many functional possibilities. Buist's slots and lobes and yokes arcing or pivoting in complicated grooves within the slots, and with an "arm projecting outward" from each one, do not serve the same purpose as my electron-receiving slot does. For Buist, again, the slot is only an axial or shoulder area groove for the movement of an arm by which to represent a variety of carbon bonds: single, double, and double-single. For me the slot always and only represents the available open space in the outer electron shell for an incoming electron from another atom to help complete the outer shell with a full complement of electrons. The arc in this slot in my model exists only to allow for allosterism, or hard alteration, of the position of the fixed incoming stud in the slot, to the right or left of the other opposite electron-stud in its slot, and of all the molecular structure synthesized behind both electron-studs, and contingent upon their mutual positions, and not the movement of an arm on a pivot.
In Buist's model there are a multitude of separate, moving parts. My model has no moving parts. And the Buist model will be extremely difficult and therefore costly to build out of plastic or metal with all of these complex flanges and grooves and separate moving parts, requiring incredibly intricate and expensive "side-actions" in plastic molds. The man who made my mold is a plastic mold maker by trade. I therefore know the great expense to construct a plastic mold for the the Buist model, probably the cheapest method of production possible. My model atom costs only 1/2 cent per piece to build with a hot plastic injection molding process. It is immensely more simple, and incomparably cheaper to fabricate.
The inventor claims that all of this movement of many separate parts will represent (1) "change in geometry" from a tetrahedral to a trigonal molecule, and (2) loss or gain of "torsional freedom" in double, single bonds, and double-single bonds; (I do not believe that double bonds are possible in the Buist model despite his claim to represent them; and I make no claim for double-bond representation with this application);
Contrastingly, in my model there are no moving parts. The movement is only allosteric adjustment, by finger and wrist twisting of the two solid, single-piece, facing atomic model units, say an oxygen and a carbon, to the right Dr to the left, pushing the two fixed studs in either direction in their counter-face receiving arcuate slots.
The allosterism which the Buist model does manage to achieve, and which is achieved with extremely complicated machinery, and without accomplishing electron pair sharing with separate electron-studs, my model achieves simultaneously, and without moving or separable arms or parts of any kind.
Further, the Buist model has "Tinkertoy"-like (tradename) male members that slide into cylindrical female shafts or barrels at the wrists of the vertically arcing arms. These are presumeably representations of electrons. The abstract does not state what they are intended to represent beyond "various torsional and configurational changes which commonly occur during chemical transformations." They cannot however represent what my model represents, namely, electron pair sharing by two physically separate studs which never touch either, like the male electron and the female electron do in Buist, but which go past each other into the opposite faces of the atom. This is the ingenious accomplishment of my invention: I give the model maker -he capacity to share a pair of electrons, to press two studs into each other's faces, but also to have the allosterism of spin about a horizontal axis between the two hands holding the two parts, that would otherwise seem possible only with a single stud in a single hole, as with poppet-beads in the well-known necklaces made from them, or as in the Buist model. In the Buist model one electron is a female and the other a male but both cannot be male representations of the electron. In my model all electrons are male; the female part of the representation is the arced slot on the flat face of each sphere, of each atom, representing the open space for an electron, the male member, to enter in order to complete the outer shell of the opposite atom. This representation does not occur in the Buist model.
Again in the Buist model the male electron and the female electron are both extended like a male member out to the tip, where one is male and one female, but both far from the body of the atom where they can unite, whereas in my model, designed to be a three-dimensional space-filling model, the electron studs are buried out of sight in the body of the atom, far closer to what really happens in chemistry, and are not visible like the long extended arms of the Buist model. In my case the small stud represents an electron. And the arced slot cut into the flat face of the sphere is arced to represent the continuum of various locations in the arc that the shared electrons may occupy overagainst each other (representing quantum/stadistical locations) in the outer shell of the receiving atom.
My model makes no claim for molecules, only for atoms, and for molecules only insofar as they are secondarily affected by the invention proposed with respect to the atomic electrons in this model.
The Buist model may be faulted from my point of view, further, since it has according to Buist's description, three (3) "equiangularly-spaced-apart arcuate slots" which are "primarily intended for the representation of carbon atoms." In another place, FIG. 1, the carbon atom is represented by five (5) extensions, which presumeably represent electrons, there also. Carbon however has four electrons to share. This equal-distanced tetrahedral character is well represented in my model with four equidistant flat faces cut (molded) onto the plastic carbon sphere, though I make no special claim for this feature, except of the stud-slot combination on each such face with its simultaneous electron-pair sharing and allosterism combination achievement.
Other models, more briefly distinguished from the model herein presented are:
(b) "Three-Dimensional Model of Molecular Structure" by Mikelsaar, U.S. Pat. No. 4,622,014, dated Nov. 11, 1986. This model has separate connecting members. In my model the connecting member, representing the electron, is part of the atom model, not a separate and separable piece. PA1 (c) "Atomic Units for Molecular Models" by Adler et al, U.S. Pat. No. 2,942,357, dated Jun. 28, 1960, seeks to provide a model which can be adjusted for "three important parameters namely, bond length, bond angle and van der Waals radii." I make no such claims of adjustability. My bond angle is always contingent upon flat face-to-face contact, and my bond length is always the same, the length of the stud. I make no claim for any van der Waals bond angles or distances. PA1 (d) "Puzzle Comprizing Interconnected Arcuate Channel Member" by Wharton, U.S. Pat. No. 4,557,482, dated Dec. 10, 1985, with its rigid chamber channels, separate set screws, marbles, etc., intends to be a puzzle, and apparently has no intention of representing atoms, or atoms in molecular arrangements, and so has no relationship to the model I propose. PA1 (e) The Jierree "Molecular Model" dated May 18, 1965, U.S. Pat. No. 3,183,608, represents the orbital rings and electrons, protons, and neutrons, internal to the atom. My model represents only the available electrons on the outer ring of the atom, each electron represented by a simple fixed single stud. PA1 (f) Another Adler. et al, model, "Atomic Units for Molecular Models," U.S. Pat. No. 2,953,860, dated Sep. 27, 1960 consists of plates, springs, screws, other threaded members, foam rubber washers, magnets, separable tapered plugs, etc. PA1 (g) U.S. Pat. No. 4,325,698, dated Apr. 28, 1987 has flexible arms radiating out from a central body with connections being made between an annularly ribbed male member and a female member. This, like the Buist model, fails the pair-sharing test, allows no allosterism between shared electron pairs, and is thus completely unlike my model. PA1 (h) U.S. Pat. No. 4,398,888, dated Aug. 16, 1983, by Darling et al, has the same extended arms, with holes at the ends for receiving similar male extensions from other similar units. However, again, the pair sharing with simultaneous allosteric capability is missing, and so is totally unlike my claim. PA1 i) Dreiding's U.S. Pat. No. 4,020,656, dated May 3, 1977 does the same thing with valence arms each containing outer and inner end extensions, therefore allowing the representation of pair-sharing, but allowing no allosterism, and certainly no simultaneous allosterism, as well as not permitting space-filling representation in which the electrons are buried in the r proper place inside the atom, such as my model allows. PA1 (j) Bramlik's U.S. Pat. No. 3,333,349 date Aug. 1, 1967 employed cuttable tubing, allowed no pair-sharing of electrons, and allowed no allosterism between shared pairs of electronstuds, as my model does. PA1 (k) Bramlik's earlier U.S. Pat. No. 3,080, 662 dated Mar. 2, 1963 had multiple subunits or pieces, one for the atom, one for connections between atoms, and one or more representing the three-dimensional character of an atomic orbital. My model is simplicity in contrast--one single piece--it has no multiple parts representing parts of the atom, but only one hot plastic injection-molded piece representing the entire atom, its covalent electrons extending from flat faces, and the capacity to pair-share electrons, and to do so allosterically, at the same time. PA1 (l) Sato, U.S. Pat. No. 3,510,962, dated May 21, 1970 attempted to represent exact bond angles within and outside of molecules. He proposed a 14-faceted polyhedral and several polyhedrals with more and fewer faces, each face with a hole into which separable rods could be inserted. I have gone way beyond this with my model of a single unit atom with opposing studs on flat faces for electrons representing in conjunction, the capacity for simultaneous electron pair-sharing and allosterism. PA1 (m) U.S. Pat. No. 3,230,643 dated January 1966, by Mathus, had a multiple-unit atom with metal tubing for the bonds. The set required gluing the plastic parts.
The Mikelsaar model also uses X-ray contras materials placed at the center of the atom spheroid for purposes of X-ray photography. I make no such claim.
The Mikelsaar model also represents electrons as single studs, but each stud fits only into a simple cylindrical hole, so that it cannot be shifted to the right or left of its point of entry; whereas in my model the receiving hole its an arced slot of 90 degrees on the flat receiving face. In the Mikelsaar model no combination of electron pair-sharing and allosterism is possible, as my model allows. exclusively.
This Adler model also claims "buttons" on the planar face which one atom unit places against another face. I know the main problem with buttons, namely, that buttons are extremely expensive to mold plastic for, requiring at least two separate side-actions in the plastic mold for each button as well as separate side actions for each face on the sphere, so I have avoided buttons entirely. I also know that buttons are very hard to work with in model building, both in insertion, and in disconnection. I also know that simple buttons do not enable a model to represent electron pair sharing. And the simple fined stud representing an electron, which my model bears, violates no one's claim.
The Adler model also allows no movement of the electron button, if that is what it is, to the right or left, with its enabling of allosteric shift, as my model does.
The addition of "T-shaped units" also rigidifies the Adler model, adds more pieces, increases the cost while losing the allosterism, and is thoroughly opposed to what my model seeks to do in combining allosterism with electron pair-sharing. Further, these T-shaped pieces or protrusions represent nothing that I know of in the real atom.
The addition of set screws and other rigidifies parts sets this model completely apart from mine.
The Jierree model also employs separable dowels and screw-in "valence-plugs" in FIG. 9 that do not even correspond with what they are asked to do in FIG. 8 of that patent description. Besides, the atom seems to be presented as a disk, rather than as a spheroid, as in my model of the atom, with concentric grooves for small balls or beads to revolve or stay fixed in, the author does not specify which.
Consequently there is no conflict between my model and the Jierree model.
My model is one single piece.

Atomic model of simultaneous electron-pair-sharing and allosterism


The invention considerably reduces the danger of deformation for containers made from a thermoplastic material during the transfer to a stacking magazine or into a locally fixed catch plate. This deformation danger results from the fact that the formed stack must be displaced within a short time by the stack distance, either through the transferred containers themselves or by components of a catch plate that is moved forward with each cycle. This is achieved through displacing the stacks in the stacking magazines or the locally fixed catch plate with a displacement device. The displacement device can be combined with the stack removal device or can be a separate displacement device. According to a modification of the invention, the method is intended to improve the cooling of the stacked containers.

This application claims the priority of German patent Application No. 100 44 228.5 filed Sep. 7, 2000, which is incorporated herein by reference.
The invention relates to a method for stacking containers of thermoplastic material, which are molded from/punched out of a heated foil web in a molding/punching tool and are transferred from this tool, either directly or indirectly, via a transfer device to a stacking magazine or to a catch plate and are removed from there as a container stack. The invention furthermore relates to a device for realizing this method.
Containers that are molded and punched out in a thermal molding machine with a combination molding and punching tool are generally transferred after ejection from the molding/punching tool to stacking magazines. This can occur directly by displacing the molding tool bottom and then transferring the containers to the stacking magazines where they are retained. A method of this type is disclosed in the German patent DE 33 46 628 C2.
A method of transferring containers with a transfer device that grips the ejected containers and, following a rotation of 180xc2x0, inserts these into the stacking magazines is furthermore disclosed in the German patent reference DE 198 52 359 A1. A non-rotating transfer device, meaning for a linear conveyance of the items, which uses a catch plate is known from the German patent reference DE 198 12 414 A1. One container is picked up during each cycle and is transferred to a stacking magazine.
The German patent reference DE 198 48 628 A1 also discloses the use of a catch plate, in which complete container stacks are formed, however, which are then transferred to a stacking magazine. The stacking magazine is then guided to a transfer location for successively conveying all stacks.
The German patent DE-AS 27 14 352 also discloses the stacking of several containers in a catch plate. The container stacks are then gripped and conveyed further with a transfer device consisting of rods.
With all these known methods, the containers forming a stack in a catch plate or a stacking magazine are displaced upon the insertion of the following container by a measure or distance that corresponds to the stack measure, meaning the distance between two neighboring stacked containers. This forward movement of the container stacks is realized in the German patent reference DE 198 12 414 A1 with the gripping elements in the shape of mandrels, which impact with points along the edge of the container that is stacked in last and thus cause the container stack to advance when the new container is transferred to the stacking magazine.
Cycle numbers of up to and exceeding 40 cycles/minute are achieved with modern automatic thermal molding machines, meaning little time is available for stacking the containers and these must consequently be stacked very quickly. In particular, this is true when stacking containers directly into stacking magazines or a locally fixed catch plate. Advancing the existing container stacks by the distance measure must occur during an interval in the order of magnitude of 0.1 seconds, which is necessary for reaching a cycle time of 1.5 seconds with 40 cycles per minute for the following processing steps: molding-cooling down-punching out-opening the tool-ejecting-closing the tool. In addition, the containers must be removed from the mold while still relatively warm, which is possible in principle, depending on the material type and thickness, but carries the danger that the containers are deformed by a mechanical force effect. This force effect occurs because the containers are moved at the bottom through the displaceable mold bottom of the molding/punching tool and hit the stack edge of the previously stacked containers with the container edge. Depending on the number of previously stacked containers and their weight, a force corresponding to the product of weightxc3x97acceleration (K=mxc3x97b) must be generated and must be absorbed by the container edge and the side walls of the container, up to the mold bottom. In particular with thin-walled containers, which permit a high cycle number due to their rapid cooling inside the molding tool, the danger of deformation of the containers is high and increases with the length of the container stack. In practical operations, the deformation danger limits the number of cycles for the device.
If the containers are advanced with the aid of the mandrels on the catch plate that is moved with each cycle (DE 198 12 414 A1), the container wall and the container bottom do not need to absorb a force during the stacking. However, the complete force for advancing a container stack now becomes effective at three or four points along the edge of the previously stacked container. The container has cooled only slightly in these 1.5 seconds, even though a cycle has passed in the meantime, so that with this forward movement of the stack, the danger of deformation at several points along the container edge exists. The driving speed of the catch plate is reduced relative to the mold bottom speed, but is still relatively high. During the available 1.5 seconds, a total distance of approximately 400 mmxe2x80x94back and forthxe2x80x94must be traversed. Even if a slower movement sequence in the end position of the catch plate movement is included in the calculation, a time in the order of magnitude of 0.3 seconds results for the actual stack lift of approximately 8 mm.
As a result of the relatively rapid stacking of containers with the known methods, as well as the associated acceleration of the complete, previously formed container stack, the danger exists that with flat containers, these will drift apart and the complete stack will thus disintegrate.
Thus, it is the object of the invention to design the method such that when transferring containers that are still warm and/or thin-walled to stacking magazines or a locally fixed catch plate, these are not deformed and do not drift apart during the stack formation, despite high cycle numbers.
The above object generally is achieved according to a first aspect of the invention by a method for forming a stack of containers of a thermoplastic material, which are molded from/punched out of a heated foil web in a molding/punching tool, which method comprises: transferring containers consecutively from the tool, either directly or indirectly, via a transfer device to a first position within one of a stacking magazine and a catch plate; using a displacement device that is separate from the transfer device, consecutively displacing each container in an axial direction of the stacking magazine or catch plate from the first position by a distance at least equal to a distance between two adjacent containers of a stack of containers to a second position within the stacking magazine or catch plate to form a stack of containers at the second position, and displace any stack of containers at the second position by at least the distance between two adjacent containers of a stack; and, subsequently axially removing the stack of containers from the stacking magazine or catch plate.
Owing to the fact that the container stacks in the stacking magazines or the locally fixed catch plate are moved with a displacement device, the displacement can occur at a slow speed and thus with little force effect on the last containers that are stacked in. For example, with a cycle number of 40/min, the displacement device has 1.5 seconds to traverse a distance in the order of 2xc3x978 mm (back and forth). Compared to the known method with movable catch plate, a displacement device can take 10 times longer and the displacement can occur at a correspondingly slower speed. The displacement by the stack measure can occur with a separate displacement unit, which only serves this purpose. The stack can be removed with a second device that is known per se, e.g., consisting of rods, once the predetermined number of containers per stack is reached.
However, the container stack can also be displaced by the stack measure with a device for removing the stacks from the stacking magazines or the locally fixed catch plate. The expenditure for this operation is low because it requires only a corresponding drive with varied lift and an adaptation of the control. However, the fact that the time needed for removing the container stacks exceeds the cycle time presents a problem. Thus, two or three containers are stacked in during the removal, without intermediate displacement of the stack measure. For the most part that is non-critical because these few containers have a low weight and no deformation must be feared. The danger only increases with a higher number of containers in the container stack.
This method also makes it possible to displace the container stack inside the stacking magazines or the locally fixed catch plate by a measure exceeding the stack measure without substantially increasing the deformation danger. As a result, it is possible to have a distance between the last container stacked in and the container stack, which is in the order of magnitude of two times to three times the stack dimension. This free-standing feature favors the cooling down of the last-stacked container on the inside surface and the last container of the stack on the outside surface, which can be improved by blowingxe2x80x94preferably cooled and/or sterilizedxe2x80x94air onto both surfaces via jets. It has turned out that the containers are still relatively warm with this high cycle number andxe2x80x94if stacked one inside the otherxe2x80x94don""t cool down well. The above-mentioned cooling step clearly improves the cooling.
The above object generally is achieved according to a second aspect of the invention by an apparatus that is connected downstream of a molding machine and comprises stacking magazines or a catch plate, into which the containers can be stacked directly or indirectly from the molding/punching tool or via a transfer device, and a stack displacement device for displacing all container stacks, which displacement device is connected to a drive and is effective with each cycle of the molding machine, said device being arranged in the region of the intake opening of the stacking magazine or the catch plate.
The method is described in further detail with schematic drawings of the device.

Method for stacking containers of thermoplastic material and device for realizing same


An adjustable wall tie for securing together spaced wythes such as a masonry veneer wall to a structural masonry wall of block-like construction. The wall incudes a tension anchor and a generally J-shaped single-ended hook adapted to engage the tension for vertical adjustment.

(i). Field of the Invention
This invention relates to an anchoring and tying device and, more particularly, relates to a vertically adjustable wall tie for securing together spaced wythes such as a masonry veneer wall to a structural masonry wall of block-like construction.
(ii). Description of the Related Art
Common residential and commercial building construction practice entails forming a brick or other masonry veneer wall adjacent a structural inner supporting wall. Generally the masonry veneer is spaced apart from the structural inner wall in a construction technique known as cavity wall construction. The air gap deters the formation and build up of damaging moisture on the structural inner wall as well as providing some thermal and acoustic insulation.
Anchors or ties are required to span the air gap at predetermined locations to secure the masonry veneer to the inner structural wall. Anchors are often formed integral with the structural wall where said structural wall is of masonry block construction. Vertically adjustable ties are required where the mortar joints of the veneer wall do not align with the the mortar joints of the structural block wall.
In the prior art it is known to use metallic elements for affixing masonry veneers to inner structural walls. U.S. Pat. No. 779,268 issued Jan. 3, 1905 discloses a combination of anchoring and tying components for use with block like members having grooves in their meeting edges. Right angled or xe2x80x98Txe2x80x99 shaped flanges formed in the anchor and tie members engage grooves in mating blocks to fixedly attach a facing wall to the support wall. This disclosure provides little vertical adjustment of the ties and is not suitable for standard bricks and blocks.
U.S. Pat. No. 1,946,732 issued Feb. 13, 1934 discloses a device for securing masonry veneer walls to structural masonry support walls. A single vertical rod is disposed on the outer face of a support wall block by means of right angularly extended end portions embedded in the mortar joints over and under said block. A bonding member attached to the vertical rod is embedded in a mortar joint of the masonry veneer. In this disclosure the vertical rod, having a length substantially the same as the relatively large standard construction block, provides ample vertical adjustment but may provide inadequate horizontal support if the bonding member is placed in the central region of the vertical rod.
In U.S. Pat. No. 3,277,626 issued Oct. 11, 1966 a double shank adjustable wall tie is disclosed for tying together spaced wythes consisting of a structural wall and a veneer wall. A planar xe2x80x9cUxe2x80x9d shaped anchor having loops formed in the free ends is disposed in the horizontal PG,4 mortar joint of the structural wall with said loops extending outward. A tie member secured in a mortar joint of the veneer wall has a base piece and a pair of outwardly extending generally parallel arms, each of said arms having a transversely turned finger at the free end thereof. Said fingers are adapted to engage the loops of the anchor member for securement of the veneer wall to the structural wall. Limited vertical adjustment is provided wherein the bond strength is decreased as engagement of the fingers in the loops decreases. For a commercially available anchor and tie device similar in principle and application to this disclosure it is recommended that vertical adjustment not exceed 11/2xe2x80x3 from the tension tie anchor to avoid possible failure by bending.
U.S. Pat. No. 5,490,366 issued Feb. 13, 1996 discloses an adjustable doubleend hook tie device for securing together a masonry veneer wall and a structural masonry wall.
It is a principal object of the present invention to provide a new and improved single end hook anchoring and tying device which may be used in residential or commercial construction employing standard masonry bricks and blocks or the like.
It is a further object of the present invention to provide enhanced vertical adjustment of the tie member with improved lateral strength and retention properties.
In its broad aspect, an adjustable wall tie of the present invention for securing spaced wythes together, each formed of courses of preformed block or brick having cementing means for joining the courses together and defining a space therebetween, comprises a rectangular tension anchor having a base member and a pair of substantially parallel longitudinal side members extending from said base member perpendicular thereto, a transverse end member parallel to the base member joining the distal ends of the side members together, and an intermediate transverse member attached to the side members in proximity to said end member forming an elongated transverse slot therebetween, said tension anchor being adapted to be positioned whereby the base member can be cemented in one of said wythes with the opposite end member with transverse slot disposed in the space between the wythes; and a generally J-shaped single-ended hook having laterally spaced longitudinal side sections and a transverse-end section joining one end of the longitudinal side sections together to form a planar base, and the opposite end of the longitudinal side sections bent at substantially 90xc2x0 to the planar base and having short perpendicular side sections reverse bent substantially 90xc2x0 parallel to the planar base and spaced therefrom, and a transverse section joining the reverse bent side sections together to form a restraining hook, whereby the planar base may be positioned in and cemented in the other of the wythes with the short perpendicular side sections disposed in the space between the wythes and the restraining hook extending through the slot of the tension anchor for tying said wythes together.
The restraining hook may be turned up or down to extend vertical adjustment of the wall tie.


A sun-tracking solar energy collector apparatus includes an east-west driving shaft body and a south-north driving shaft body which are coupled in the shape of a cross. A first driving member of an east-west shaft sleeve of the east-west driving shaft body is actuated to turn the south-north driving shaft body in an east-west direction. A second driving member of the south-north driving shaft body is driven by the first driving member to turn an east-west driving shaft of the east-west driving shaft body in a south-north direction and to drive an annular member which is connected with the ends of the east-west driving shaft, such that a holding rack assembly connected with the annular member is actuated in east-west and south-north directions. Solar energy collector modules of the holding rack assembly can track to collect solar energy. Due to the base body in cooperation with the effect of tracking sun, the area occupied by the base body is larger. Thus, the surroundings of the base body can be adapted for parking, charging of a motor-driven vehicle and the like, enhancing its total generating capacity and providing better usage.

1. Field of the Invention
The present invention relates to a sun-tracking solar energy collector apparatus, in particular to a sun-tracking apparatus capable of automatically changing the angle of solar energy collector modules so as to collect the sun light directly and efficiently.
2. Description of the Prior Art
Following the development and change of human civilization, the consumption of energy sources is increasingly great. However, the energy sources, such as petroleum, natural gas, coal, and so on, may be used up some day. Besides, the greenhouse effect becomes a big problem because the concentration of carbon dioxide gradually increases. The climate of the earth is extraordinary changing. Thus, energy-saving and carbon reduction is a worldwide plan. Solar energy is the greatest natural energy of the earth. The energy of the sunlight to the ground every day is a quarter of the global petroleum reserves. The solar energy does not pollute the environment. Furthermore, the semiconductor materials are developed rapidly, so the collection of the solar energy is improved. Because the radiation of the solar energy is in a distributed way, the intensity of the light is low, not more than 1,000 watt/square meter. A conventional solar energy collector apparatus comprises a pillar and a solar energy collector module which is obliquely connected to the pillar. There are some shortcomings in the prior art:
1. Low generating capacity: the solar energy collector module is obliquely connected to the pillar, which is unable to collect the solar energy effectively because the change of the incidence of the sunlight.
2. Insufficient functionality of usage: the solar energy collector module is obliquely connected to the pillar. When the incidence of the sunlight is changed, the solar energy collector module is unable to change its angle relative to the pillar accordingly. Besides, the solar energy collector module is only adapted to collect the solar energy, without any other additional functions.

Sun-tracking solar energy collector apparatus


Three-dimensional large scale bodies such as jumbo aircraft fuselages (14) are assembled in body sections around a central longitudinal assembly core (1) which itself is mounted at its ends and accessible all around along its length. Robots carrying tools for holding, transporting and precisely positioning pre-assembled wall shell sections, are movable along the central core (1). First, at least one floor grid (2 or 3) is releasably mounted to the core. Then, side wall shell sections (4, 5) are secured to the floor grids. Then, top and bottom wall shell sections (10, 8) are secured to the side wall shell sections (4, 5) to form a body section (BS) of the large scale body (14). Neighboring body sections are secured to each other along cross-seams. Upon completion, the floor grids are released from the core (1) and the core is removed preferably withdrawn longitudinally from the assembled large component or body.

This application is based on and claims the priority under 35 U.S.C. xc2xa7119 of German Patent Application 199 29 471.2, filed on Jun. 26, 1999, the entire disclosure of which is incorporated herein by reference.
The invention relates to an apparatus for producing large three-dimensional structural components such as an aircraft fuselage or the like having an elongated barrel-shaped configuration or an oval or circular cross-section.
So-called large volume or jumbo aircraft have fuselages assembled from shell sections, preferably shell sections reinforced by load supporting elements such as stringers and spars or ribs. One or more plate-shaped floor grids are mounted inside such large scale fuselages. The floor grids extend longitudinally inside the fuselage and from one side wall to the opposite side wall.
German Patent Publication DE 34 38 584 A1 discloses an apparatus for the manufacture of an aircraft fuselage, whereby large surface area, curved structural elements are assembled to form fuselage sections. These fuselage sections are then interconnected by an automatically operating orbital riveting machine and by manual labor to form fuselage components. The riveting takes place along so-called cross-seams, whereby the automatic orbital riveting machine travels along these cross-seams guided by a machine guide rail extending as a ring around the aircraft body or fuselage. The entire orbital riveting machine or system is mounted on a carriage that can travel along or rather in parallel to the longitudinal aircraft axis also referred to as the X-axis.
In the manufacture of aircraft fuselages, it is further known to assemble subassemblies in rigid jigs that determine the geometry of the subassembly. Such rigid jigs operate on the principle of orienting all subassemblies relative to a zero position in a rigid system. According to such a known system, the preassembled subassemblies are deposited in jigs and located relative to fixed system points with a so-called zero alignment. Such a zero alignment system has the disadvantages that the zero alignment can result in deviations, particularly along the interface between individually neighboring subassemblies. Such deviations can fall outside permissible tolerance ranges. Moreover, an adjusting of the individual subassemblies in order to assure the desired overall geometry of the aircraft fuselage is not possible. However, as long as the fuselage has a circular cross-section that is a cylindrical configuration, the use of the zero alignment or positioning is possible, whereby the subassemblies forming the lower body half are positioned and riveted first whereupon the cabin floor is inserted and connected with the spars or ribs of the lower body half. A so-called auxiliary carrier, also referred to as a presenting frame, holds the subassembly relative to the jig and tool system in position without any possibility of making compensating adjustments in the positioning. Thus, positional deviations of the floor structure relative to the fuselage body are possible, but cannot be corrected. Once the floor structure and the lower fuselage half are assembled, the upper side wall shell sections and upper shell sections are secured to the lower half, whereby the positioning is again performed by way of the above-mentioned zero alignment.
Efforts have been made for avoiding some of the above described drawbacks. Thus, U.S. Pat. No. 5,694,690 (Micale) describes a method for producing large scale aircraft bodies from a plurality of subassemblies, whereby the subassemblies or selected components of the subassemblies are provided with drilled coordination holes for an accurate positioning and assembly of the subassemblies. The coordination holes make sure that the elements of the subassembly are already accurately positioned relative to each other so that the resulting subassemblies become self-locating and thus intrinsically determine the final contour of the aircraft body independently of tooling. The drilling of the coordination holes is accomplished by a computer controlled precision robot which is directed to the drilling locations using a digital data set taken directly from original digital part definition records.
The above described methods leave room for improvement, especially with regard to reducing the assembly costs while still assuring the required accuracy in the configuration of the final large scale product, such as a fuselage for a jumbo aircraft.
In view of the above it is the aim of the invention to achieve the following objects singly or in combination:
to provide an assembly apparatus for producing large scale components such as jumbo aircraft bodies, whereby the assembly permits maintaining required, precise tolerance ranges without the need for high precision jigs and without drilling precisely positioned locating holes, while still assuring the accuracy of the three-dimensional large scale body;
to substantially increase the accessibility of tools to the assembly positions for performing most assembly work by robots, particularly the forming of longitudinal and cross-seams; and
to provide a system and apparatus which substantially is independent of the length of the large scale body so that substantially any required number of subassemblies can be jointed to each other without any additional matching adjustments so that an entire aircraft fuselage can be assembled.
The above objects have been achieved by performing the following steps with the aid of the apparatus according to the invention. A prefabricated longitudinal central assembly core is mounted at its ends, for example between support columns. Then, at least one floor grid is secured to the assembly core with the aid of clamping tools which mechanically fasten the floor grid to the core. Then, shell-shaped sections having a defined internal stiffness of their own are positioned by robot tools which are preferably computer controlled, sequentially around the central assembly core and then mechanically interconnected, for example by riveting. The positioning is performed in such a way that first side wall shell sections are positioned opposite one another and secured to the floor grid or grids by mechanical means. Thereafter, bottom shell sections and top shell sections are sequentially secured to the side shells and to one another to form individual body sections of the large body such as a fuselage which is then completed by interconnecting individual body sections to each other, for example by riveting along cross-seams.
It is an important advantage of the invention that the assembly of the prefabricated shell sections or subsections can take place within a precise tolerance range, whereby, for example an aircraft fuselage section can be assembled with the required precision, yet without jigs or locating holes. All prefabricated subsections are positioned relative to the central prefabricated core which itself is lightweight and has its own stiffness. The core forms part of the assembly station and can be reused. The prefabricated fuselage planking is mounted to the floor grid or to the floor grids held in precise positions by the central longitudinal assembly core. By first mounting the side wall shell sections to the floor grid or grids, it becomes possible to mount or assemble the bottom fuselage shell section and the top shell section to the side shells without any difficulties. In a preferred form, the side wall shells are first secured to the floor grid or grids in a row, whereupon the upper and lower shells can also be secured in respective rows to the row of side wall shells.
According to a preferred embodiment of the present method, the three-dimensional large structural component is assembled of at least two body sections which are interconnected by the above-mentioned cross-seam, whereby each individual body section is so formed that the lateral or side shells are positioned opposite each other and are mechanically connected to the floor grid or grids to form a first subsection. Then the respective upper and/or lower shells are mechanically connected to the two side wall shells to form the first body section. Once the first body section is assembled the second section is assembled in the same manner and further sections are assembled next to the already assembled sections. Each body section is mechanically connected, e.g. by riveting, to the preceding body section along the cross-seams.
The apparatus according to the invention comprises a combination of the following features. An elongated central assembly core for holding at least one or more floor grids is secured with one end to a mounting held for example in a column, while the other end of the core is secured to a second mounting. Both mountings hold the core in a precise position relative to the longitudinal axis of a large scale body to be assembled. Tool means in the form of movable robots are provided for positioning body shell sections relative to the assembly core and relative to each other. A central processing unit is operatively connected to the tool means for controlling the tool means when they perform a holding, transporting and positioning operation for the assembly of shell sections relative to the floor grid or grids held by the core, whereupon additional tools perform the securing operations.
When the assembly is completed, the large scale body is supported by other supports, the central assembly core is released from the floor grids and removed from the body, for example by pulling the core longitudinally out of the body.

Apparatus for assembling a three-dimensional structural component


A method of packaging and dispensing a packaged mechanical part is disclosed. The method includes the steps of placing a plurality of substantially flat mechanical parts having an adhesive-coated surface, including a release backing protecting the coated surface on an adhesive coated flexible film. The parts are oriented such that the release backing contacts the adhesive coating on the flexible film. A second flexible film is positioned over the first film, encapsulating each part and forming a flexible, continuous container. The container is then opened by simultaneously separating the first and second flexible films while rolling the first flexible film over an edged surface, proximate the point of separation of the two films. The method advantageously removes the release backing while delivering the part from the packaging. The part is delivered in a condition which is substantially free of mechanical damage and contamination.

The present invention relates to packaging for mechanical parts. In particular, it relates to a packaging method for protecting mechanical parts during handling and dispensing to prevent contamination and avoid component damage.
In many industries, it is important to package and handle individual parts to avoid contamination and/or damage. The computer industry is an example. The present invention is described in the context of a computer hard disk but has applications beyond that component and industry.
Hard disk files are computer components which store information. A hard disk file typically has a magnetic recording disk and a magnetic read/write transducer for writing information onto the disk, and reading information from the disk. The transducer is mounted onto a magnetic recording head, which is supported by a spring attached to an actuator arm.
The spring, or flexure provides a force normal to the disk surface which allows the head to remain positioned very close to the disk surface as the disk spins. When the disk is spinning, an air cushion forms between the disk surface and the adjacent head surface, forcing the head away from the disk, in a direction normal to the disk surface. The spring, or flexure provides a force in a direction normal to the disk surface, which compensates for lifting motion of the magnetic recording head, and causes the head to remain close to the disk surface. When the disk comes to rest, the spring presses the head against the disk surface.
During disk file operation, the disk spins and a servo motor positions the magnetic read/write transducer above a track on the disk. As the servo motor moves the head from track to track on the disk surface, the acceleration of the actuator arm causes vibration in the actuator arm spring, which in turn causes the magnetic read/write transducer to vibrate. Also, movement of the head from position to position within the same track causes the actuator spring to oscillate. It is necessary to dampen the vibration in the spring of the actuator arm to maximize the speed in which the hard disk file operates. This dampening may be accomplished by a damper positioned on the spring.
Although it is known in the industry that placing a damper on the actuator arm spring is desirable, it has not been possible prior to the present invention, to handle the dampers without causing some contamination and/or damage. Contaminated and/or damaged dampers often cause the entire hard disk file component to fail quality control tests. The quality control failure of a hard disk file actuator arm, for example, requires that the actuator arm be returned to a clean room atmosphere and thoroughly cleaned before the defective damper is removed and replaced. Recleaning and repairing these components has proven to be both time consuming and expensive.
Presently, dampers are punch pressed from a strip of base stock material, which in a preferred embodiment is a multilayer laminate containing at least one layer of stainless steel. The total laminate thickness is typically about 0.003 inch thick. The stock material 10 is shown in FIG. 1 and has a lower surface which is coated with an adhesive (not shown). A release backing (not shown) is provided in the form of a release tape to protect the adhesive coating, and to prevent the dampers from adhering to the surfaces prior to their desired placement. The dampers 12 are punched from the stock material 10 with a punch press and are immediately returned to their original positions in the cut-out portions of the stock material. When the dampers are cut, the adhesive layer and release backing are also cut. As the dampers are returned to the cut-out areas of the sheet, the edges of the adhesive coating on the dampers bond to the outer edges of the cut-out areas, holding the dampers in place, forming a sheet of dampers as shown in FIG. 1. The dampers may be handled/shipped as a sheet prior to their use.
In order to use the dampers, it is necessary to first separate each damper from the sheet of dampers 10. Presently, this tedious task is accomplished by using very small tools such as tweezers, a pin vice, or a small knife for example. A typical damper 12 is of a substantially wedged shape which is less than one inch in length, and less than one quarter of an inch in width at the widest end. Individually removing each damper has proven to be very difficult and time consuming, and often results in mechanical damage such as dimpling, bending, and nicking. Physically handling the parts also creates more opportunity for exposure to contaminants.
Once each damper/backing has been separated from the sheet, the release backing must next be removed. A common release backing is available in the form of a release tape, and is typically constructed of paper which is coated with a wax or silicone. Although the bond between the adhesive and the wax coated paper is relatively weak, manufacturers who use the dampers have still found it difficult to remove the paper backing from the damper itself, due to the small size of the part. Removing the paper backing often requires the use of tools such as tweezers. This removal procedure often results in bending, and other mechanical damage to the dampers such as nicks, as well as contamination. The above-mentioned procedures are also time consuming and expensive.
Manufacturers of computer components have discovered that the use and handling of actuator arm spring dampers described above results in significant contamination and/or mechanical damage. If the damage or contamination goes undetected, reduced hard disk file performance or possible catastrophic disk drive failure is likely to be a result. If the damage or contamination is detected, additional disassembly, cleaning, and assembly steps are required to produce an acceptable product.
It is known in the art to deliver mechanical parts on a continuous, adhesive coated tape. For example, Okui U.S. Pat. No. 4,702,788 discloses a carrier tape structure having a first film layer with a series of aligned holes near the edge of the tape for receiving the teeth of a sprocket, and another series of aligned apertures near the center of the tape for receiving mechanical parts. Beneath the first film layer is attached a second film layer having an adhesive coating on both sides. The second film layer is wide enough to completely cover the apertures for receiving parts, but is narrow enough to avoid covering the sprocket holes. On the opposite side of the second film layer is a protective peel-off layer. Parts are positioned on the exposed adhesive surfaces on the first film layer. The second layer is severed along the boundary of each aperture so that when a part is removed, the portion of the second film layer contacting a surface of the part is removed with the part.

Method of packaging and dispensing a mechanical part


A multilayer polymeric film comprises:

The present invention relates to a multilayer polymeric film. More particularly, the present invention relates to a multilayer polymeric film with a skin layer having a non-migratory polydimethylsiloxane block copolymer.
In the packaging of certain types of foods, such as snack foods including candies, potato chips, cookies and the like, it is common practice to employ a multi-layer film. Polypropylene films are widely used in the packaging industry due to their superior physical properties, such as, transparency, stiffness, moisture barrier characteristics and others. Despite these highly desirable properties, unmodified polypropylene film has the disadvantageous property of having a high inherent coefficient of friction and film-to-film destructive blocking on storage. This high film-to-film coefficient of friction makes polypropylene films, in their unmodified form, difficult to use in automatic packaging equipment.
Coefficient of friction characteristics of polypropylene and other thermoplastic films are beneficially modified by the inclusion of slip agents in the polymer. Most of these slip agents are migratory, such as polydiallyl siloxane or fatty amides, such as, erucamide and oleamide. Although they do reduce the coefficient of friction, their effectiveness depends upon the ability to migrate to the surface of the film. The development of the desired low coefficient of friction value is strongly dependent upon the type and amounts of amides, and time and temperature aging effects. Even the heat history of the film while in storage and shipping and during subsequent converter processes, significantly affects the coefficient of friction. In addition, the presence of these types of fatty acid amides on the film surface results in visible adverse appearance effects, manifested by an increase in haze, a decrease in gloss and the presence of streaks. These materials also adversely effect the wettability and adhesion of solvent and water-based inks, coatings and adhesives.
To overcome the problems associated with migratory slip agents, non-migratory systems were developed. A material described to be a non-migratory slip agent is a particulate crosslinked hydrocarbyl-substituted polysiloxane which is available worldwide from Toshiba Silicone Co., Ltd. and in the United States from General Electric Co. And marketed under the name TOSPEARL.
In PCT US94/14280 a film structure containing a non-migratory particulate crosslinked hydrocarbyl-substituted polysiloxane slip agent is described. The film structure includes at least one layer of an olefin homo-, co- or terpolymer having a surface-treated external surface which is printable, sealable and machinable The film has, as a combined slip agent and antiblock, a non-migratory particulate crosslinked hydrocarbyl-substituted polysiloxane, and/or liquid polydimethyl siloxane. Example 7 provides a polypropylene core layer having (a) an outer skin layer of high density polyethylene containing particulate crosslinked polymonoalkylsiloxane as a non-migratory combined antiblock and slip agent and low density polyethylene. On the other side of the core layer is (c) an outer layer resin which also contains the non-migratory combined antiblock and slip agent. The film is flame treated on one side to improve the wettability and printability and lamination strengths. The size of the particulate in terms of average diameter is about 4.5xcexc. The target skin thickness of the (a) layer is three gauge units and four gauge units for the (c) layer The ratio of particle size in terms of average diameter to skin thickness is about 5.9 for the three gauge skin layer and about 4.42 for the four gauge skin layer. The film is described as having good coefficient of friction, on the treated side, and marginal machinability.
Additional descriptions of olefinic polymer films in which particulate siloxane resins are employed to provide improved films will be found in U.S. Pat. Nos. 4,966,933; 4,769,418; 4,652,618; and 4,594,134.
U.S. Pat. No. 4,966,933 describes a propylene polymer film containing 100 parts by weight of a propylene polymer, 0.01 to 0.5 parts by weight of a fine powder of a crosslinked silicone resin and 0.3 to 3.0 parts by weight of a hydroxy-fatty acid glyceride. In column 3, lines 6-20, the provided amounts of fine powder of silicone resin and hydroxy-fatty acid glyceride in the metallization layer are required for adaptability to vacuum deposition. Example 3 provides a two-layer coextruded film in which the fine powder of crosslinked silicone resin is compounded with polypropylene homopolymer to form a metallization layer (B) and the fine powder of crosslinked silicone resin is compounded with an ethylene/propylene/butene-1 copolymer to form a skin layer (A). The ratio of reported particle size to skin thickness is about 0.143 for skin layer (B) and about 1.29 for skin layer (A).
U.S. Pat. No. 4,734,317 to Bothe, et al. discloses a biaxially oriented multilayer polyolefin film which comprises a polypropylene base layer, a first polyolefin sealing layer positioned on one side of the base layer, and containing from about 0.5% to 3% by weight of incorporated polydialkylsiloxane, the first sealing layer not being subject to corona treatment, and a second polyolefin sealing layer positioned on the other side of the base layer and having a coating of the polydialkylsiloxane on its outer surface, the second sealing layer being subject to corona treatment, wherein the polydialkylsiloxane coating is formed by contact of the first and second layers.
U.S. Pat. No. 4,925,728 to Crass, et al. discloses a biaxially stretched multilayer film comprising a base layer essentially comprising polypropylene and at least one top layer, wherein the top layer essentially comprises (a) 98.5% to 99.6% by weight of a propylene homopolymer and (b) 0.4% to 1.5% by weight of a polydiorganosiloxane, relative to the top layer.
U.S. Pat. No. 5,482,780 to Wilkie, et al. discloses a polypropylene film with cold seal release and cold seal receptive surfaces, wherein a predominantly isotactic polypropylene homopolymer core has on one side thereof an ethylene-propylene random copolymer having a physically modified surface for reception of a cold seal cohesive composition and on the other side of the core there is a blend of an ethylene-butylene copolymer and an ethylene-propylene random copolymer containing a non-migratory slip agent. The preferred non-migratory slip agent is described as being a crosslinked silicone having a particle size of about 1 to 4.5 microns, such as that identified by TOSPEARL of Toshiba Company.
U.S. Pat. No. 5,489,473 to Wilkie discloses biaxially oriented polypropylene cold seal packaging films comprising at least one cold seal release layer and a cold seal receptive layer. The use of crosslinked silicone in the cold seal release skin layer is also disclosed.
U.S. Pat. No. 5,792,549 to Wilkie discloses a coextruded biaxially oriented polyolefin packaging film comprising a cold seal release layer, a core layer, and a cold seal receptive skin layer. The use of crosslinked silicone having a particle size of about 1 to about 4.5 microns such as that identified by TOSPEARL of Toshiba Company is also disclosed.
U.S. Pat. No. 5,798,174 to Wilkie discloses cold sealable films for heat sensitive packaging operations comprising, in order, a cold seal cohesive layer, a core layer, and a cold seal release layer comprising a mixture of about 1 to about 80% by weight butene-propylene copolymer and about 99 to 20% by weight butylene-ethylene copolymer.
U.S. Pat. No. 5,840,419 to Alder discloses a multilayer polyolefin film comprising a core layer of a propylene polymer and an outer polyolefin layer on the core layer, the outer polyolefin layer including a coefficient reducing amount of a particulate, partially crosslinked polysiloxane, which are preferably in the form of elastomeric particles including polysiloxane in the form of silicone oil. The patent states that the silicone oil is released when the particles are xe2x80x9csubjected to mechanical stress.xe2x80x9d
U.S. Pat. No. 5,858,552 to Bader, et al. discloses a film structure having a first outer skin layer (a) of an olefin co- or terpolymer containing a non-migratory particulate crosslinked hydrocarbyl substituted polysiloxane, a core layer (b) and a second skin layer (c) of an ethylene polymer which is free of the particulate crosslinked hydrocarbyl substituted polysiloxane in layer (a).
Commonly-owned, copending U.S. application Ser. No. 09/026,454, which is incorporated herein by reference, discloses and claims a block resistant film comprising: (a) a core layer of a thermoplastic polymer, the core layer having a first side and a second side; (b) a functional layer which is printable or sealable or treatable for printing or sealing on the first side of the core layer; and (c) a block-resistant layer on the second side of the core layer comprising a thermoplastic polymer and an amount of polydialkylsiloxane, based upon the entire weight of the block-resistant layer, sufficient to inhibit blocking of the block-resistant layer to the functional layer when they are in contact and which polydialkylsiloxane deposits silicon onto the functional layer but the amount deposited is not substantially detrimental to the printing function or the sealing function.
There is provided a multilayer polymeric film comprising:
(a) a core layer comprising a thermoplastic polymer; and
(b) at least one skin layer comprising a thermoplastic polymer and a nonmigratory polydimethylsiloxane block copolymer.
The core layer comprises a thermoplastic polymer which has properties suitable for extrusion or coextrusion. The extruded or coextruded film may be biaxially oriented in the machine and transverse directions under elevated temperature so as to form a multi-layer film. Although the preferred thermoplastic polymer of the core layer is a polypropylene homopolymer, other polymers may be used. These polymers include polymers made from one or more 2 to 4 carbon atom olefins, such as ethylene or butene-1, or a polymer made predominantly of propylene with minor amounts of another olefin, usually a 2 or 4 carbon atom olefin.
Optionally, the core layer comprises an antistatic agent in addition to the thermoplastic polymer. The antistatic agent may be selected from, e.g., glycerol monostearate (GMS) and a blend of GMS and tertiary amine. Suitable amounts for the antistatic agent may range from about 0.05% to about 3 weight %, based upon on the weight of the core layer.
A skin layer may comprise a polymer which is the same or different as the polymer of the core layer. Suitable polymers include an olefinic polymer, such as polypropylene or polyethylene. Other suitable polymers include a copolymer or terpolymer of ethylene, propylene and/or butylene and/or another olefin having 5 to 10 carbon atoms or a mixture of these olefin polymers. Particular skin layers comprise an ethylene homopolymer having a density of about 0.91 to about 0.96 g/cm3, an ethylene-propylene copolymer in which the ethylene content is about 2 to about 10% by weight based upon the total weight of the copolymer, or an ethylene-propylene-butylene terpolymer in which the ethylene content is about 0.5 to about 7 weight % ethylene and about 5 to about 30 weight % butylene, each based upon the total weight of the terpolymer. Other resins used to form skin layers include ethylene-vinyl alcohol copolymer (EVOH) and ethylene vinylacetate copolymer (EVA).
In one embodiment, the multi-layer film may comprise (a) an upper skin layer which comprises a non-migratory polydimethylsiloxane block copolymer, (b) a core layer, and (c) a lower skin layer which is substantially free of non-migratory polydimethylsiloxane block copolymer. As will be appreciated by those skilled in the art, the use of the terms upper and lower to refer to particular skin layers is merely relative. Moreover, although referred to as skin layers, the upper and lower layers may have additional structures bonded thereto, based on the functional requirements of the overall structure.
The polymer materials which may be used in forming skin layer (a) include heat sealable polyolefinic copolymers and terpolymers and blends thereof The copolymers include block copolymers, for example of ethylene and propylene, and random copolymers, for example of ethylene and propylene. Terpolymers are exemplified by ethylene-propylene-butene-1 terpolymers. Also, heat sealable blends can be utilized in providing layer (a). Thus, along with the copolymer or terpolymer there can be polypropylene homopolymer, e.g., one which is the same as, or different from, the polypropylene homopolymer constituting core layer (b) or other material which does not impair the heat sealability of this layer.
Suitable ethylene-propylene-butene-1 (EPB) terpolymers include those obtained from the random inter-polymerization of from about 1 to about 8 weight percent ethylene, preferably from about 3 to about 7 weight percent ethylene with from about 1 to about 10 weight percent butene-1, preferably from about 2 to about 8 weight percent butene-1, with propylene representing the balance. The foregoing EPB terpolymers may have a melt index at 230xc2x0 C. of from about 2 to about 16, e.g., from about 3 to about 7, a crystalline melting point of from about 100xc2x0 C. to about 140xc2x0 C., an average molecular weight of from about 25,000 to about 100,000, and a density within the range of from about 0.89 to about 0.92 gm/cm3.
The ethylene-propylene (EP) random copolymers may contain from about 2 to about 8 weight percent ethylene, e.g., about 3 to about 7 weight percent ethylene, the balance being made up of propylene. The copolymers may have a melt index at 230xc2x0 C. ranging from about 2 to about 15 and preferably from about 3 to about 8. The crystalline melting point may be from about 125xc2x0 C. to about 150xc2x0 C. and the number average molecular weight range may be from about 25,000 to 100,000. The density may range from about 0.89 to about 0.92 gn/cm3.
When blends of EPB terpolymer and EP random copolymer are used, such blends may contain from about 10 to about 90 weight percent EPB terpolymer and preferably from about 40 to about 60 weight percent EPB terpolymer, the balance being made up of EP random copolymer.
Prior to extrusion, the heat seal layer (a) is compounded with an effective amount of a slip agent comprising a non-migratory polydimethylsiloxane block copolymer. By non-migratory, it is meant that these block copolymers do not change location throughout the layers of the film in the manner of the migratory slip agents, e.g., polydialkylsiloxane or fatty amides. The amount employed may range from about 0.01% to about 0.5% by weight, for example, about 0.1% to about 0.4% by weight, based upon the entire weight of the skin layer resin.
The polydialkylsiloxane block copolymer may be in the form of a di-block, tri-block, or star block copolymer. Either block component of the block copolymer may be compatible or incompatible with the polymer or polymers in the skin layer. Examples of the polydialkylsiloxane block copolymer include dimethylsiloxane-alkylene ether block copolymer; dimethylsiloxane-arylene ether block copolymer, dimethylsiloxane-vinyl block copolymer; dimethylsiloxane-ester block copolymer (such as bisphenol A carbonate-dimethylsiloxane block copolymer; 9,9-bis(4-hydroxy-phenyl)fluorene carbonate dimethylsiloxane block copolymer, tetrabromobisphenol A carbonate dimethylsiloxane block copolymer; and 2,2,4,4-tetramethyl-1,3-cyclobutylene carbonate dimethylsiloxane block copolymer); aryl-alkyl phthalates dimethylsiloxane block copolymer (such as bisphenol A isophthalate dimethylsiloxane block copolymer; bisphenol A terephthalate dimethylsiloxane block copolymer; and hexamethylene terephthalate dimethylsiloxane block copolymer); polycaprolactam dimethylsiloxane block copolymer; polyurethane dimethylsiloxane block copolymer; dimethylsiloxane olefin block copolymer; and blends thereof
Polymers for use in forming lower skin layer (c) include ethylene polymers such as linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) or blends thereof Other resins include ethylene-vinyl alcohol copolymer (EVOH), ethylene-vinyl acetate copolymer (EVA) and polypropylene homopolymer. High density polyethylene may have a density ranging from between about 0.94 to 0.96 gm/cm3 and over. Skin layer (c) of the particular three-layered film structure described above is formed without adding the non-migratory polydimethylsiloxane block copolymer, which is included in the formulation of skin layer (a). Thus, skin layer (c) is considered to be substantially free of the non-migratory polydimethylsiloxane block copolymer used in skin layer (a). This does not, however, exclude the incidental presence of non-migratory polydimethylsiloxane block copolymer which might occur upon subsequent handling of the finished film, for example, upon winding the film onto a roll, whereby non-migratory polydimethylsiloxane block copolymer from skin layer (a) might be sloughed onto the external surface of or imbedded into skin layer (c). In one particular embodiment, skin layer (c) consists essentially of high density polyethylene.
Either or both layers (a) and (c) can also contain pigments, fillers, stabilizers, light protective agents or other suitable modifying ingredients if desired. Further, skin layers (a) and/or (c) can optionally contain a minor amount of an additional antiblock material, such as, clays, talc, glass, and the like. These antiblock materials can be used alone, or different sizes and shapes can be blended to optimize machinability. The major proportion of these particles, for example, anywhere from more than half to as high as 90 weight percent or more, may be of such a size that a significant portion of their surface area, will extend beyond the exposed surface of such skin layer.
The multi-layer film may have one or more additional layers in addition to core and skin layers. Such an additional layer may be comprised of a polypropylene homopolymer, such as highly crystalline polypropylene (HCPP), which may help to improve release properties of the film. HCPP polypropylene polymers include those having a decalin solubles content of about 1 to about 5% by weight, meso pentads equal to or greater than about 85% (13C NMR spectroscopy), and a melt flow of about 2.5 to about 3 (as measured according to the standard ASTM D1238 test for polypropylene).
Suitable commercially available HCPP polymers include, but are not limited to, Amoco 9218 HCPP resin from BP-Amoco.
Additional layers may, optionally, contain a solid or liqiud antiblock. The solid antiblocks may be such that they do not substantially break up when subjected to mechanical stress like the particulate, partially cross-linked polysiloxanes described in U.S. Pat. No. 5,840,419. Suitable antiblocks include, but are not limited to, fully crosslinked or non-meltable polysiloxane, polymethyl methacrylate (PMMA) particles such as EPOSTAR(copyright) MA-1002 or silica particles such as SYLOBLOC 44 from W. R. Grace. Silicone oil is an example of a liquid antiblock. An example of a fully crosslinked or non-meltable polysiloxane is TOSPEARL T120A, available from Toshiba Silicone Company, Ltd.
The solid antiblock may be incorporated into the additional layer in an amount ranging from about 0.1 to about 0.5% by weight, preferably from about 0.15 to about 0.30% by weight, based on the entire weight of the additional layer.
Silicone oil, e.g. polydimethylsiloxane, may be used in the additional layer in a range from about 1,000 centistoke (cs) viscosity to about 100,000 cs viscosity. Preferred silicone oils are those having a viscosity of about 30,000 to about 60,000 cs, such as 20/30,0000 polydimethylsiloxane fluid from Dow-Coming or 200/60,0000 polydimethylsiloxane fluid from Dow-Corning.
The silicone oil may be incorporated into the additional layer in an amount ranging from about 0.1 to about 2% by weight, preferably from about 0.2 to about 0.8% by weight, based on the entire weight of the additional layer.
One or both of the skin layers may be a functional layer suitable for being treated for printing or sealing or by being a thermoplastic polymer which is printable or sealable without treatment. Such a functional layer may be selected from the group consisting of ethylene or propylene homopolymer, ethylene-propylene copolymer or ethylene-propylene-butylene terpolymer or a mixture of two or more of such homopolymer, copolymer or terpolymer. The surface of the functional layer may be treated by surface treatment which improves wettability and adhesion of printed matter (print may be by lithography, liquid or dry toner, thermal dyes, dye sublimation, etc.). In another embodiment, the functional layer is a cold seal adhesion promoting layer.
The functional layer may itself be printable or sealable or may be treated so as to provide sealability and/or printability. This treatment includes surface treatment of any kind known to enhance the surface tension properties such as flame or corona treatment. Other treatment methods include the application of a printable or sealable covering layer by way of any conventional extrusion or coating method. Certain water-based coatings are known for their utility as cold-sealable coatings or printable coatings. Examples include acrylic-based coatings including alkyl acrylate polymers and copolymers.
Sometimes it is useful to enhance or provide the film with certain properties by use of appropriate film additives. Such additives are used in effective amounts, which vary depending upon the property required, and are, typically selected from the group consisting of antistatic, antiblock, slip, antioxidant, moisture or gas barrier additives. These additives may be added to one or more layers of the film according to the present invention.
Useful antistatic additives which can be used in amounts ranging from about 0.05 to about 3 weight %, based upon the weight of the layer, include alkali metal sulfonates, polyether-modified polydiorganosiloxanes, polyalkylphenylsiloxanes and tertiary amines. As discussed previously for the core layer, the antistatic agent may be GMS or a blend of GMS and tertiary amine.
Useful antiblock additives used in amounts ranging from about 0.1 weight % to about 3 weight % based upon the entire weight of the layer include inorganic particulates such as silicon dioxide, e.g., a particulate antiblock sold by W. R. Grace under the trademark SYLOBLOC 44, Sipernat from Degussa, calcium carbonate, magnesium silicate, aluminum silicate, calcium phosphate, and the like (e.g. KAOPOLITE). Another useful particulate antiblock agent is TOSPEARL made by Toshiba Silicone Co., Ltd. and is described in U.S. Pat. No. 4,769,418. Another useful antiblock additive is a spherical particle made from methyl methacrylate resin having an average diameter of 1 to 15 microns, and such an additive is sold under the trademark EPOSTAR and is commercially available from Nippon Shokubai.
Slip additives include higher aliphatic acid amides, higher aliphatic acid esters, waxes and metal soaps, which can be used in amounts ranging from about 0.1 to about 2 weight percent based on the total weight of the layer. A specific example of a fatty amide slip additive is erucamide.
Antioxidants, such as phenolic antioxidants, may be used in amounts ranging from about 0.1 weight % to about 2 weight percent, based on the total weight of the layer. An example of an antioxidant is commercially available under the trademark IRGANOX 1010.
Barrier additives may be used and may include low-molecular weight resins, hydrocarbon resins, particularly petroleum resins, styrene resins, cyclopentadiene resins and terpene resins.
Optionally, the outer layers are compounded with a wax for lubricity. Amounts of wax range from about 2 to about 15 weight % based on the total weight of the layer.
The multi-layer film may also comprise additional coatings and/or layers such as an adhesive layer (e.g., a water-based urethane coating), a metallized polyester layer, and/or a cold seal layer (e.g., Technical Coatings 30061A, which is a pattern applied coating comprising polyisoprene and ethylene-vinyl acetate copolymer), as is well known in the art.
The film may be formed by coextruding the thermoplastic polymer-containing core layer together with the at least one skin layer and optional additional layers through a flat sheet extruder die at a temperature ranging from between about 200 to about 275xc2x0 C., casting the film onto a cooling drum and quenching the film. The sheet may then be stretched about 4 to about 6 times in the machine direction (MD) orienter followed by stretching about 6 to about 10 times in the transverse direction (TD) orienter. The film may then be wound onto a reel. Optionally, one of the external surfaces is coated or flame or corona treated before winding (i.e., the surface of the functional skin layer). In addition, the production process may also be modified to include an adhesive layer on one or both surfaces of the multilayer polymeric film, a metallized polyester layer, and a cold seal layer.
An example of a multi-layer film comprises three layers: the core layer, an outermost skin layer comprising a non-migratory polydimethylsiloxane block copolymer, and an outermost skin later which is functional. However, it is contemplated that intermediate additional layers can be incorporated between the core layer and the outermost skin layers. The core layer may represent about 70 to about 90 percent of the thickness of the total multilayer polymeric film. The skin layers are usually coextensively applied to each major surface of the core layer, typically by coextrusion, as noted above. However, skin layers arrived at by coextrusion may not, ultimately, be the outermost layers.

Multilayer polymeric film with non-migratory antiblock agent

Abstract: A multilayer polymeric film comprises:

Abstract: (b) at least one skin layer comprising a thermoplastic polymer and a non-migratory polydimethylsiloxane block copolymer.


A fabric having one or more guides attached to a wear surface of the fabric so to encapsulate fifty percent or more of the fabric caliper. Advantageously, the encapsulation of the fabric by the guide, and not the chemical affinity of the materials, is the mechanism that attaches the guide and fabric. Consequently, the bond strength is equal to the tear strength of either the fabric or guide material alone.

In the papermaking industry, there is an apparatus which is used to thicken pulp and paper stock. Early on such devices were commonly referred to as deckers. These early devices involved the use of cylinder molds which included a porous cylinder mold rotating in a vat of liquid with a controlled input of slurry. Water would be drained off through the cylinder mold thus thickening the remaining slurry which would be drained off. An example of this type of device can be found in U.S. Pat. No. 4,106,980.
An improvement on the then conventional thickeners can be found in U.S. Pat. No. 4,722,793. This patent describes a device which avoids the use of a cylinder mold. It employs a single pair of smooth-surfaced rolls and a single fabric trained around those rolls so that it wraps substantially 180° of the surface of each roll. The pulp stock to be thickened is initially delivered to the inside of a fabric run approaching the top of one roll so that the pulp is trapped in a zone between the fabric and the roll and is made to travel around the roll with the fabric. Centrifugal force causes liquid to be expressed through the fabric from the pulp trapped between the fabric and the roll.
The resulting partially dewatered pulp then travels on a lower fabric run to the other roll, where it is similarly subjected to centrifugal force causing further expression of liquid through the fabric. After travelling around the surfaces of both rolls, the pulp is removed from the surface of the second roll.
In order to guide the fabric in a path perpendicular to the axes of the two rolls, the fabric was provided along one or both of its edges on its bottom surfaces with a strip of material or guide in the shape of a V-belt. This guide was intended to fit into a peripheral groove in each of the rolls.
This belt is made separate from the fabric and mechanically attached thereto. Due, however, to the high-speed operation of the device, difficulty was encountered in maintaining the guide on the fabric.
In an effort to improve on this arrangement, U.S. Pat. No. 5,039,412 teaches providing for stitching the V-belt guide to the fabric and providing a band of adhesive on the fabric in the area of the stitching. The application of the adhesive extends a short distance inward from the side of the fabric. Also, guides are provided on the outer edge of the fabric so that they are positioned on the outside of the rolls rather than in a groove or grooves in the rolls.
In other industrial belting applications, certain machines have been constructed without any controlled mechanical active guiding system. These types of machines require belt fabrics with very secure v-guides on the wear side for frictional guiding against the outer edges of rolls, or in specific grooves in the rolls machined at either edge or in the center thereof. In addition, the fabric must maintain a low coefficient of friction on its wear side to facilitate machine thread-up.
The current industry standard for these types of machines include permeable fabrics with v-guides secured by one or a combination of the following four methods: 1) sewing the v-guide onto the fabric using various types of monofilament or multifilament threads; 2) gluing the v-guide onto the fabric by choosing appropriate combinations of glue and v-guide materials to create a chemical bond; 3) filling the fabric structure with the same material used to manufacture the v-guide, to create a bond through fusion upon heating and mating both surfaces under pressure; and 4) priming the fabric with a material chemically compatible to that used in the v-guide, so to create a combination of chemical and thermal surface fusion upon mating both structures under heat and pressure.
U.S. Pat. No. 5,039,412 (discussed above), U.S. Pat. Nos. 5,558,926 and 5,840,378 (discussed later) all teach applications of the first, second and third methods. In addition, the fourth method has been and continues to be used in the production of impermeable/solid belting.
Unfortunately, all the above methods have certain drawbacks. For example, the sewing method is susceptible to fatigue failure due to both flexing of the threads, and to the abrasion on the exposed opposite side of the fabric to which the v-guide is attached. On the other hand, the second, third and fourth methods depend on a surface bond between two interfaces, which is a function of both the available surface area as well as the chemical affinity between the two materials. Although methods two through four avoid the abrasion problem of method one, the less than ideal bonding and flex fatigue at the interface may nevertheless impair durability. A related disadvantage is that the bond strength between the fabric and v-guide is always less than the tear strength of either the fabric or v-guide materials alone. This allows for the possibility of v-guide delamination.
In other belt applications, single or multi-ply polyurethane, polyvinyl chloride, or synthetic rubber structures supplied as flat stock are threaded and joined endless on the machine, via either a non-marking pin seam, or via splicing using a time consuming skiving and chemical bonding type process. The high degree of available surface area for bonding on the wear side of these structures makes it possible to attach v-guides using a simple melt fusion process, with or without surface priming (depending on the compatibility between polymer types in the belt and v-guides). However, the disadvantage with this method is, again, that the bond strength is always less than the tear strength of either the belting or v-guide materials alone.
In view of the foregoing, it is desirable to employ a non-marking, pin-seamable fabric in these applications, so to avoid the excessive time and inconvenience of the skiving and bonding process which requires expensive outside contractors to perform this specialized time-consuming process. In this connection, it has been suggested that a coated, spiral fabric might provide an easy-to-pin, non-marking seamable structure. On the other hand, currently available coated spiral structures are difficult to produce with v-guides for two reasons. First, unfilled constructions with less than 0.20 mm plane difference on the v-guide bonding surface exhibit insufficient surface area for fusion bonding. Second, fully filled structures with uniformly smooth bonding surfaces offer little durability advantages over the current standards—again, due to the bond strength being less than the tear strength of either of the two laminates.
Other prior art includes the following:
U.S. Pat. No. 5,466,339 is a conventional seamed papermaking felt. Extruded monofilaments are secured in a machine direction to the underside of the felt in a spaced parallel relation and overlie the area of the seam protecting the seam from abrasion;
U.S. Pat. No. 5,840,378 is an endless woven papermachine belt with an anti-flexing part of thermoplastic resin provided at the edges of the paper side and a guide ridge of thermoplastic resin at the edges of the machine side. The guide ridges are welded integrally with the anti-flexing parts;
U.S. Pat. No. 6,214,752 is a shoe press jacket with a woven base fabric. One surface is coated with resin and the full thickness of the fabric is filled with this resin. A coated layer is formed on the other side;
U.S. Pat. No. 6,465,074 is a resin-impregnated endless extended nip-press or calendar belt with a woven base fabric. This woven fabric includes elements which have been coated with a first polymeric resin material. At least one of the surfaces of the belt is coated with a second polymeric material. The first and second polymers have an affinity for each other so that the second coating establishes a chemical interlock with the elements having the first coating;
U.S. Pat. No. 5,558,926 discloses a bending resistant part of a fabric, formed by filling a polyurethane resin in the internal structure of the fabric. A guide protrusion molded from similar polyurethane is arranged on the bending resistant part by fusion. Cutting caused by bending and wearing of the fabric near the guide protrusion is purportedly prevented;
U.S. Pat. No. 3,523,867 is a wire belt for Fourdrinier machines. On the edges of the belt, woven or cut to width, there are laid up to about ten reinforcing strands, preferably of plastics material. The strands provide reinforcement for the edges and resist damage and cracking, without stiffening the belt unduly or making it thicker;
U.S. Pat. No. 5,384,014 is an apparatus for thickening a suspension of solid particles in liquid. The device employs rolls each having a headbox which delivers a flow of the suspension to be thickened in such manner that it is trapped between the wire and the portion of the roll wrapped by the wire. The trapped suspension is thus dewatered and concentrated by expression of liquid through the wire; and
U.S. Pat. No. 5,731,059 is a dryer fabric formed with a plurality of silicone strips along its edge portions to prevent wear due to abrasion and heat. The silicone rubber encapsulates the end portions and the edges of the yarns, forming beads along the outer surfaces of the dryer fabric which separate the yarns from direct contact with the drums.
While some or all of the foregoing references have certain attendant advantages, further improvements and/or alternative forms, are always desirable.