PH26719A - A method a binder and a binding machines for closing hose or bag shaped packings primarily tubular food packings - Google Patents

Description

vi METHOD A BINDER AND A BINDING MACHINE ~ FOR CLOSING HOSE OR BAG SHAPED PACKINGS,

PRIMARILY TUBULAR FOODSTUFF PACKINGS

RACKGROUND OF THE INVENTION

The present invention relates to a method of closing hose or hag shaped packings, primarily foodstuff packings, whereby a constricted portion of the racking is clamped by a ring shaped non-metallic clamp hinder, which is caused to he narrowed ahout the constriction hy a closing pressure applied from opposite sides thereof and is fixed in its shape as attained when it is subjected tn a closing pressure.

Typical packings will be sdusage articles, which have a porous sausage ckin of a bhirous material, and hag or sausage shaped packings for other kinds of « foodstuffs, e.g. soups, the packing material here being: ; wo a tight, tubular plastic sheet material. The sausage skin materials are porous hecause the products should he suhjected to a smoking treatment, wherehy they are given ! both a desired taste and a long durahility, while the plastic sheet material should he as tight as possible for rendering the packed products as durahle Aas possible,

In both cases almost the same prohlem exists, namely that the binding of the constrictions should be effected very tightly such that in case of sausages the clamp binders will not slide on the narmally very slippery sausage skins hefore and during the smoking, while the clamps when mounted on the plastic sheet an envelopes should likewise he non-slidable, but also provide for an effective sealing against penetration of air, In both cases it is normally necessary to make use

. . . 26%] . 26719 of clamping forces which are so high that a potential danger of the sheet material being damaged will exist, and, in fact, it is well known that in the relevant productions a most significant waste on this account is heing experienced.

For these types of bindings it has been customary, almost exclusively, to use binders of the metallic clip type, j.e. U- or C-shaped metal strips, which are introduced over a constriction area of the packing and hent by reasonahly high clamping forces so as to he closed as a ring ahout the constriction. Much could be said about the advantages and disadvantages of these metal clips, but here it should just be mentioned that they are responsible for the high waste, because they have a limited ahility to hold the material tightly clamped, and that they show a major disadvantage in just heing of metal, Generally, according to modern standards, any kind of metal is unwanted in connection with foodstuff articles, It is relevant to mention also that it has heen found that the metal clips are simply unable to close the plastic sheet packings with any particularly high degree of tightness, at least not without an associated highly potential danger of damaging the material so that the «closure will he untight anyhow. Through the recent vears several extremely tight plastic sheet material have heen developed for increasing the storage durability of the various foodstuff products, but it has been realized that these developments are in fact superfluous as long an as the materials cannot be closed with the same high degree of tightness.

Already for leaving the use fo metal there have heen some attempts to make use of plastic binders, hut the designs of these hinders have nat heen suitable for use with large <ize packings, i.e, packings with relatively thick conctriction areas, An advantage of the plastic hinders, apart from their not beings of metal is that thev may he provided with locking means such that they mav he tichiened ahont the constriction area and he fixed to closed ring shape, whereby they may clamp the constriction area with high forces without these farces heing limited by the ahility of the binder material to retain a hent shape against return-hending forces from the clamped constriction area.

The already known plastic binders, however, suffer from various drawbacks which will nai be discussed in great detail in the present context. Generally they are hased on the same hasic ideas as the metal clips, namely that they should serve to surround the constriction area with sufficient tightness to he non-slidingly secured and to provide a high degree of sealing of the constriction area. Most of the known plastic binders are unusahle for large size packings because they comprise a U-shaped portion, the legs of which are received in a hole in an opposed counter portion, wherehy the constriction material will he clamped against the edges of the receiver hole, and this may give rise to concentrated clamping forces which cause a rupturing of the sheet material.

There are not either, =o far, any reports on an plastic binders heing applicable to effect any "super gealing” of the relevant constriction areas,

In connection with the invention a major prohlem has heen found in the fact that it is in neo way ideal to effect a binding of a constriction area hy way of a circularly annular hinder or a hinder having major portions shaped in this manner. Experiments and calculations have shown that what happens is a peripheral compaction which forms a harrier against the clamping pressure heing transferred ta the inner portions of the constriction area. When a high pressure is applied the relatively thin layer of the compacted peripheral material will he axially displaced by flowing, but since the material is frictionally cohering with the inner material the latter will he axially drawn by such displacement and deformation of the onter material. This drawing is effected based on the resiliency of the nonflowing material, and it may well happen that by an applied high clamping pressure the inner material next to the material in the zone of flowing material will hereby be stretched beyond its so-called rupture prolongation, i.e. the material will hurst.

The ahave considerations apply to casing materials nf plastic, but similar considerations may apply to casings of fihrous material, and in both cases the result will he that in fact none of the known binders are optimal with respect to creating a high clamping pressure in a safe manner, i.e, without damaging the casing material.

The considerable waste should be seen on the 320 hackground that apparently it has not earlier heen realized what is really happening in the constriction 4

I area when a high clamping pressure is applied from hinder portions of varions configurations; and it is heliever that the present invention represents a pioneer work in this respect, For the normal nse of metal clips it is typical that some empiric tests are made at the beginning of a production, such that the waste can he held as low as possible and that an attempt to reduce the waate further hy lowering the clamping pressure will only result in a similar or even worse waste, now not hy rupturing the material but by the binders nnt heing safely held on the casings. It is a traditional counter measure to mount two or more clips at each constriction, but the waste percentage will still he high, and as far as an extremely sealed closing is concerned such a series of clips will he of no help at all, as none of the clips will have any chance of providing for a "super sealing".

As will he apparent from the foregoing the main purpose of the invention is to provide a method and a hinder which will enahle the canstrictions to he bound bv a relatively high hinding pressure with a very low risk of the consiriction material being damaged, such that the waste can he reduced considerahly or even he eliminated. Raced nn the same contribution it is =a further purpnse of the invention ta provide a method and : a binder which will he applicable for obtaining a "super sealed” closing of the constrictions, this of course . alan heing of utmost importance. i

According to the new concept of the invention it 20 has heen found that for a practically ideal relation between a high «clamping pressure and a low risk of damaging the «casing material the constriction area should he clamped hetween opposed surface portions of substantially straight clamping beams of the binder ~lamp and he caused to he compacted into a final shape, in which it is cross sectionally oblong in the longitudinal direction of the substantially parallel clamping beams, preferably with a length at least twice the distance hetween the clamping heams, Ohvionsly the applied clamping pressure and the size of the hinder should still he adapted to the particular production, but already with a conventional adaptation in this respect, i.e, hy empirical selection of the conditions, the result will be a drastic reduction of the waste percentage, hecause with the said disposition of the constriction area hetween substantially parallel clamping heams a relatively very high clamping pressure can he applied without damaging the casing material,

The invention is based on advanced studies of the : hehaviour of the casings material in the constriction area when exposed to a clamping pressure, and it has even been found that it is possible to select a correct hinder and clamping pressure based on the known basic or starting parameters of the process, i.e, the dimensions and material constants of the casing material, thus without relying solely on empirical tests, It is helieved, however, that in the present connection it will he unnecessary to elucidate the theoretical basis of the invention when the result thereof can he expressed in terms of concise and novel method and design conditions,

Briefly, the physical effect of applying the

A clamping pressure helween straight and parallel clamping heams will he that the clamping pressure is transferred to the inner material portions in the constriction area without heing hindered hy any compaction taking place lengthwise of the clamping heams as wonld acony along curved clamping means, sand the clamping pressure, therefore, will he taken up hy the constriction area in a relatively very "soft" manner involving no drastic differences in the hehavionr of the different neighhnring lavers of the material in the constriction area. Correspondingly, the physical effect of the constriction area being elongated in the direction is that the degree of campaction of the constriction area will he relatively small, whereby it is ensured that the different material portions as frictionally engaging each ather by the compression thereaf will not give rise to substantial rubbing effects, such that the casing material is unlikely to he ruptured hereby.

The required clamping together of two opposed clamping heams to a desired final position is achievable with the nse of clamping heams which are essentially rigid or stiff, and which are interconnected endwise through tensile strong leg portions of which at least one ia adapted to he received in a in Aa receiver opening in the opposite clamping beam in a length variable and fixahle manner. Tn any production there will he some variations in the general thickness of the constriction areas, and, consequently, the leg portion will intrude more or less in the receiver opening or even protrude more or less (rom the rear side nf the opposite clamping heam., Correspondingly, in arder to limit the number of 7

’ different standard hinders it may be desirable, for a given production, tn select a hinder type which will give rise to such rearwardly protruding leg ends, and generally this will he disadvantageous in that projecting binder portions will present a tearing risk ‘ towards neighboring packings. In the prior art, as far az plastic hinders are concerned, the same problem has existed, though to a much higher extent hecause of the larger displacement of the leg portion during the clamping operation, and it has been suggested in that cannection that the prohlem of the widely rearwardly projecting leg ends may he solved by simply cutting away these protruding portions immediately at the rear side of the hinder portion from which they project, This, however, has turned out to he an unacceptable solution of the problem, bhecanse in connection with the production of foodstuff products it is highly unacrceptahle to have loose cut off binder portions ncenrring together with the products themselves,

With the present invention it is ensured that a given binder type having a specific length of the leg portion is usahle in connection with an increased number of different products and their associated variations of the general thickness of the constriction areas, because with the oblong configuration of the clamped constriction area the intrusion or protrusion of the leg portion into or beyond the receiver opening will vary relatively little dite to the associated small clamping displacement of the leg portion, It is practically a0 possible, therefore, to entirely avoid the cutting of the leg portions hy prescribing either the use of such a : R thickness nf the receiver clamping heam that the end of the leg portion will remain inside the receiver opening despite the occurring thickness variations of the constriction areas or, where the leg memhers will protrude moderately from the rear sides of the receiving clamping heams, that the onter ends of the leg portions he smoothly rounded so that these end portions will not present any tearing risks, TIlerehy each standard hinder type will he applicahle for the bhinding of both a variety of different products and for the binding of standard products showing a low tolerance with respect to the general thirkness of the constriction areas, without the end portions of the leg memhers having to he cut away,

While these results of the invention are highly : important it wmav he still more important that the invention provides for a practical possibility of a "super sealed” closure to he obtained in a well defined and reproduceahle manner. It has heen found that the main condition af a super tight rlosure is in fact rather simple to formulate and to realize based on the principles of the inventinn, while at the same time it has heen made clear why such a closure is otherwise practically unachievable.

In order to provide a full sealing all material portions across the constriction area should he pressed firmly together as well as firmly against the surrounding clamp. Inside the constriction area and on the surface thereof, due to wrinkles and foldings of the raging sheet, there will exist a plurality of unclosed narrnw channels, which will not he rlngsed mevely by a

’ pressure sufficient to force the sheet surface sub areas tightly together, In order to close these channels it js simply necessary to subject the material at each relevant place to such a high pressure that the plastic material is deformed, hy a real deformation flowing, and hecanse the wrinkles may occur all over the constricted arena the condition of really producing a totally sealed closure will he that each and all sub portions of the constricted area are subjected to such a high deformation pressure without any portion therenf herehy being fractured,

The building up of such a high and non-damaging pressure even inside the central portion of the area is generally possible with the use of the method according to the invention, while with the use of the conventional metal clips there are several sub areas in which the pressure will he either too high or teo low, or, in other words, it is impossible to avoid the situation that the pressure is suitable in some sub areas without being either too low or too high in other =sub areas, whereby the result is hound to be nnsuccessful,

Some of the already known plastic binders could he hetter suited for providing a less varying pressure in the constriction area, but here one prohlem is that the sheet material, as already mentioned, is forced against the edge of a hole so as to readily burst at this place by an applied high pressure, and another problem is that in the prior art it has generally heen endeavored to produce Aa finally hound constriction area of approximately uniform thickness and width, It has now been found, both theoretically and experimentally, that a deformation pressure midwavs in the constriction area cannnt in practice be built up without the remaining material heing damaged, unless the thickness, i.e. the distance hetween the appnsed clamping beams, is noticeably smaller than the width of the area, Likewise it is imporfiant that the binding is effected between substantially straight, opposed clamp portions.

In practice, in a given production, it should of course he ascertained that the clamping pressure is adjusted so as to he affective far the desired result {an he ohtained, i.e. high enough to cause an overall flowing deformation of the material, but without having caused damage to anv part of the material. These functions cannot he directly observed, hut test samples may he produced for heing tested and inspected, The fulfilling of the conditions for obtaining a "super sealed” closure according to the invention can he verified bv removing the clamp and broadening out the tubular casing material of the constriction and then (1) inspecting the material for ohservable fractures, and (2) wmeasuring the sheet thickness all the way round to make anre that at every sub area the sheet material has undergone the deformation flowing, this being inherently connected with an axial displacement of the material and therewith with a permanent thickness reduction thereof,

Thus, when the material is unhroken and is of reduced thickness all the way over the former constriction area, then the applied pressure has been correct and applied carrectly for providing the super sealing effect, and a0 the production may start or continue with the same mounting conditions for mounting the hinders of the

} | particular selected type.

With the use of plastic binders it is inevitable that the hinder after the fixation thereof and after the removal of the applied pressing tools will expand bh somewhat under the influence of the resilient expansion forces in the cowpressed material in the constriction area. Normally this will he acceptable, hecause it has heen found that the high degree of sealing as having heen achieved hy the applied high clamping pressure will remain unchanging high even hy a considerable pressure relief thereafter.

The fixation of the hinder, ie. the locking of the connector legs to the clamping beams, should be effected such that no significant return movement will accur after the relief of the clamping tool pressure.

According to the above, however, a certain small amount of return movement may be acceptable anyway, which may largely facilitate the designing of well suited binders.

For achieving a perfect sealing of or in the constriction area it will normally be necessary to compress the material hy some 10-50% all according to the cross sectional shape of the area and the E-module of the particular plastic sheet material, i.e, a quite considerahle axial displacement of the material should he effected for making sure that all kinds of axial leaks have heen sealed off. Particularly with the use of cheet materials of a low E-module it may he disadvantageous for the integrity of the material to use a strongly binding ring memher of small "height", i.e. of a small axial dimension, because the outermost material in the constriction area may then burst by the forceful clamping together of the correspandingly thin clamping beams of the hinder. Tdeally for this purpose a rather high ar lang hinder should he nsed, which will distribute the pressure over an enlarged outer area of the constriction and thus he more lenient to the sheet material. This material should still be clamped sufficiently for an overall expansion in the axial direction, but with the use of a relatively long binder the axial expansion will he smoothened ont and he partly suppressed in that the expansion forces will be taken up hy counter resilient forces from the material portions frictionally held by the hinder adjacent the axial end portions thereof.

However, such long hinders will he correspondingly expensive, and for the invention it is an important recognition that a corresponding result will he ahtainahle with the nae of "shart" hinders, viz. hy =a suitable design of the tanls used for the clamping actuation of the hinders. Thus, this desired effect will he achievable hy externally holding the material of the constriction area just outside the hinding area in siueh a manner that the held material cannot he freely axially displaced, this heing effectable hy means of special clamping tno! portiens, which, in conjunction with the clamping together nf the binder, will clamp against the constricted material area just outside the opposed ends of the hinder. Herehy there is provided a frictional resistance against the axial expansion of the material, what will carvespond to an increase of the FE- module in the actual binding area, such that high clamping forces may be applied to a "short" binder

‘ © without the material being damaged. When the clamping pressure is relieved and the clamping tool portions are removed the hinding pressure may cause a certain post- expansion, hut as already mentioned it will he unimportant whether an associated pressure reduction inside the bound area will oceur, when it has only’ previously heen ensured that a real compaction and axial displacement of all sub portions of the material in the hinding area has been obtained.

It is important that the hinder opening is he forehand disposed approximately in accordance with the crocs sectional shape of the constriction area, such that the casing material hy its compaction between the clamping beams shall not have to he widely laterally deformed in order to engage the cross leg connection hetween the clamping beams.

The invention, which is more closely defined in the appended claims, will now he described in more detail with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective exploded view of a hinder according to the invention,

FIRS. 2-4 are schematic views illustrating the use of the hinder,

FIGS. 5 and 6 are a perspective and a sectional view, respectively, of a modified binder,

FIGS. 7 and 8 are corresponding views of two other emhoadiments of the binder,

FIG. 9 is a perspective view of still a further hinder embodiment, shown preparatory to being used,

FIGS, 10-13 are plan views illustrating the progress of a "super sealing” binding.

FIGS. 14-17 are corresponding longitudinally sectional views,

FIG. 18 is =a schematic plan view of another modified hinder,

FIG. 19 is a side view, partly in section, illustrating hinding operation with additional tools heing use,

FIG. 20 is a corresponding perspective view,

FIG. 21 is a perspective view illustrating the application of a binder onto a constricted packing portion, and

FIG. 22 is a corresponding top view, partly in section,

DETAILED DESCRIPTION

The hinder shown in FIGS. 1-4 includes a U-shaped member generally designated by the reference numeral 2 having a clamp heam 4 and two legs 6, and a relatively thick, lonse clamp black heam 8 with two throughgoing hales 10 for accommndating the legs 6. The ends of the smooth legs 6 are provided with longitudinal slots 12 having slightly undulated side walls, and on each leg end is provided a wedge body 14, forwardly protruding and held hy an easily hreakable connection 16 to the leg end such that the connection 16 is hroken when the wedge hody 14 is pushed into the slot 12, wherehy the leg end portion will be laterally expanded, Also the lateral walle of the wedge hady 14 are andulated,

The wedge hndies 14 are located such that they may be introduced intn the holes 10, see FIG. 2, when the ‘

’ two hinder parts 2 and 8 are brought together about a constriction 18 non a tubular packing having an outer sheet casing. Ry a further pressing together of the parts as illustrated hy pressure arrows in FIG. 3 the clamp heams 4 and R are caused to effect a desired, predetermined closing pressure on the constriction 18, which is hereby compressed to a certain thickness within a given tolerance range. Far the particular production a clamp 2,8 has heen selected, which is adapted to the total cross sectional area of the casing sheet such that in the final positinn the constriction 18 will fill out, entirely or just almost, the full space between the legs f# when the hinding area of the binder has adopted a share which is oblong in the longitudinal direction of the parallel heams 4 and R. Preferahly, the width hetween the legs 6 should be at least twice the distance between the beams 4 and 8,

When the hinder assumes ite final position between non-illustrated clamping tnols, the wedge hodies 14 are pressed nor beaten into the slots 12, see FIG. 4, whereby the end portions of the legs A will expand inside the holes 10 and thus be locked against retraction therefrom. For improving this locking the holes 10 may diverge slightly rearwardly or be pravided with a slightly nartowed entrance end,

If the product to be bound is of the sausage type, i.e. having a porous rasing, it will be sufficient if the space between the legs 6 is just almost filled out by the constriction 1R, while if, a super tight closure nf a plastic casing is desired this space should be entirely filled out, as explained below in more detail.

However, in both cases the oblong shape of the conatrictinn area hetween the heams 4 and 8 will condition a relatively high clamping pressnve tao he n=ed without the crazing material bursting, so in hnth cases an exceptionally firm holding of the clamp on the concgtriction is achievahle.

Moreover it can he ensured in both cases that the free ends of the legs f may be laecated entirely within the holes 10, such that they will not form rearwardly protruding tearing members, This will be a question of adapting the thickness nf the block lieam 8 to the expected or kuown tolerance of the total crass certinnal aren of {he casing na forming the consecntive constrictions 18, In practice, of conrse, only A limited nimher of hloack heams 8 with different thickness will he available for a carvrespondingly limited number . nf different distances hetween the holes 10, but even so it has heen found that relatively few different standard hinder «izes will be <«ufficient for the practical demand. Tt may happen that the leg ends will protrude somewhat fram the rear side of the black beam 8, irrespective of the manner in which the legs 6 are fixed ta the hlock beam 8, and this may be acceptahle if the free ends of the less AB are shaped smanthly rounded ta still not form regular tearing memhers and =till not require to he ont off.

The problem as to freely projecting leg ends might of course he avercome by using very thick block heams 8 as a standard, hut any unnecessary oversize will imply unneceasary costa, and this jis important hecanse hinders for the digecussed purposes are used in millions or

: ‘ rather hillions.

As mentioned the opposed clamp beams 4 and 8 should ideally he straight and remain straight, though a slightly arched shape could he acceptable. The constriction 18 will seek to expand and thus to hend the heams 4,8 outwardly, The hlock beam 8, dae tn its enlarged thickness, will not easily bend, hut the heam 4 would have to he equally heavily designed if it should resist any trace of bending out once the clamping tool pressure has heen relieved. To avoid such overdimensioning of this heam 4, the tool clamping pressure may he increased to somewhat ahove the desired final pressure, such that just this pressure is established when the binder leaves the tools and the beam 4 is bent out slightly hy the internal pressure of the constriction 18, Alternatively the clamping pressure could be applied hetween the block heam 8 and the local foremost end areas of the legs 6, i.e. on the outer ends of the beam portion 4, and this beam portion conld extend slightly inwardly curved so as to he straightened out when the clamping pressure is applied to the foremost leg end areas only. Also, the clamping tool cooperating with the heam 4 may he slightly curved to produce the same result.

In FIGS, f and 6 is shown a binder, in which a metal pin 20 is prepositioned in the respective end portions of the block beam 8 without from the heginning projecting into the respective holes 10. Jt will be appreciated that the legs 6 are here lockable in their final positions by the pins 20 heing forced towards each other sa as ta penetrate the leg end portions and intrude into the interior wall material of the holes 10, as shown in the left hand side of FIG. 6, As shown in dotted Ines in the right hand side {thereof the free end of the legs mav he amnothly rounded as suggested abave, such that they need not he cut away even if they finally project somewhat hevond the rear cide of the block heam 8.

Tn the binder shown in FIG. 7, the Jegz 6 are shaped with transverae middle slnta 22, which may cooperate with a wedge member 24 associated with the respective end paortiang of the black heam R, provided in a recess therein and operable to be pushed inwardly into the =<lot. 22 for locking the leg ends by expansion therenf,

In FIG. 8 is shown a hinder in which the beam partions 4 and 8& are permanently interconnected at one end through a leg portion 7, which constitutes or includes a hinge portion, whereby the two heams 4,8 are closahle fram the opened position shown in full lines to the closed pocilion shown in dotted lines. Herehy a free leg portion 26 on the heam 4 is introduceable into an apertured leg portion 28 on the free end of the heam

R, the aperture being designated 20. The leg portion 26 is provided with barb like protrusions 32 and the aperture 30 has corresponding, inverted barb portions 34, whirh will effectively hald the leg portion 26 against retraction from the hole 30 once it has heen introduced therein. Tn this case, as conld he the case wilh the legs 6 of the (oregaing Fignres, the leg ic not 0 fivable exactly in the position in which it is left hy the final clamping pressure on the heams 4 and RR, hut as

: . mentioned hereinhefore a small degree of retraction will normally he acceptable. The heams 4 and 8 could he straight as in the other examples, but FIG. ] illustrates that some stight curving of the beams may he acceptahle, as it would even in the other Figures, When the length nf the leg 7 is not adjustable the heams 4 and 8, in their final positions, may not he fully parallel, but again, a small deviation from the ideal circumstances will generally be allowable without the . 10 major advantages heing sacrificed.

In FIG. 9 is shown a plastic hinder comprising a :

U-shaped member 26 having a bottom beam a8 with forwardly protruding legs 40 and a loose cross beam 42 ‘ shaped with holes 44 for receiving the legs 40, It is indicated that the U-member 36 is inserted laterally over a constricted area 46 of a tubnlar packing 4R, which may contain a rigid, semi rigid or liquid foodstuff. The nutsides nf the legs 40 are provided with small harbhs 50 adapted to cooperate with corresponding holding ribs 52 on the outer side walls of each nf the holes 44.

The hinding of the constriction area 48 is effected hy a simple farcing together of the heamn portions 38 and 42 with the legs 40 received in the 28 holes 44, The objective here is tn effect a super sealed” hinding of the constriction area 46 of a very tight packing material designated 53 of plastic. It is not presupposed that this material is particularly orderly disposed in the constricted area by a controlled pleating or otherwise, but only that the material bas been gathered together and is now located inside the opening of the U-membher 36, whereafter thie memher j= hrought together with the cross beam 42.

Tn this initial phase, in which the ends of the legs 40 may only just reach the front ends af the hnles 44 when the sheel material of the constriction 16 starts ten resist the moving together nf the beams 38 and 42, the sheet material 53 will thns still he only loosely packed together, and it will not even fill out the hinder opening, see FIG. 10.

In a following secand phase, see FIG. 11, the heams 38 and 412 are forced together until a full compaction has heen established, i.e. until practically all axial passageways through the hinder area have been closed, principally corresponding to the area of the hinder opening now heing almost equal to the total cross aectional area of the tuhular material 52. The material 52 will be subjected to the highest pressure in the areas thereof whirh are located directly adjacent the middle areas of the opposed clamping beams, while the pressure will decrease towards zero adjacent the corner areas as long as the deformable sheet material may =till seek ontwardly towards these areas, Just hecause the material is deformable it will hereby, in the areas of the said higher pressure, he somewhat axially expanded before an initial building up of the pressure adjacent the corner areas, and when this happens the tntal croas sect innal area of the sheet material will already he somewhat vediiced compared with the same area in a free condition of the sheet material.

The sheet material will he pressed laterally ontwardly against the middle portions of the legs 40

' already hefore the material is pressed out into the corners of the binding opening, and at these places, therefore, =a pair of opposed compression areas will occur, which, via the internal friction in the material of the compacted canstriction area, will act as pressure hridges between the respective opposed end portions of the clamping beams 38 and 42. Herehy the applied clamping force on the clamping beams 38, 42 will not he immediately transferred to the rentral area of the hinding area, and also for this reason the provision of an initial pressure build up in each and every portion of the hinding cross section will require an already established, relatively considerable clamping force on the clamping beams, wherehy a certain axial expansion will he applied to the sheet material located immediately next to the middle portions of the clamping heams 38,42 and the connector legs 40, respectively.

It is corresponding circumstances which, as mentioned, will make it impossihle to ohtain a sufficiently high closing pressure in a constriction area which is narrowed generally along a circular peripheral length or partial length, hecause an associated building up of a peripheral pressure hridge may simply prevent any considerable pressure build-up in the central area as long as the applied pressure is not so high as to damage the surface material,

The same will apply to the hinder shown if the effective length of the legs 40 is larger than the effective length of the beams 38,42 or even larger than just the half of the latter length, In that case the pressure bridges along the legs 40 will he so pronounced that by a further clamping together of the beams 38,43 it ig jmpessible to build up an initial pressure in the central area of the constriction hefore the material in the pressure hridges has heen compressed tao such a degree as to he damaged, whereafter a complete sealing is unachievable.

This is why it is important that the hinding cross section he pronnunced flat hetween the clamping heams.

In order to provide for a complete sealing the heams 38,42 are forced further together, iG, 12, wherehy the constriction material will be positively deformed and axially expanded in each and every sub portion of the cross section. The degree of axial expansion will not be the same all over the area, but this is immaterial if it has only been achieved that in all suh portions some expansion has taken place,

When the clamping tools are removed from the hinder, FIG. 13, the heams may hnlge out somewhat, but an associated pressure reduction in the deformed constriction area is well acceptahle once the overall deformation has heen ohtained, Due to the barb portions 50,52 the U-member 36 is self locking in the position in which it was left hy the removal of the clamping tools, hut if the harhs are course a certain return displacement may take place, but again, this may he arceptahle, particularly if the E-module of the material iz low, For higher F-modules it will be preferable to use a hinder of a stepless self-locking type, e.g. as shown in FIGS, 1-7,

The pressure distribution in the middle area of the constriction is shown graphically in FIGS. 14-17, in

: which partly common pressure levels designated a-d are shown.

Level a, which is practically zero, represents the pressure in the gathered together, hut still non- a compacted constriction (FIGS. 9 and 10).

Level h, FIG. 15, represents the slightly increased pressure in the middle of the area when the clamp beams have advanced to the complete compaction of the material as discussed in connection with FIG. 11.

It will he noted that the pressure next to the clamp heams is somewhat above level h.

Level c¢ indicates the maximum pressure .in the central area upon the pressure deformation of the material, FIG. 12.

Level d, FIG. 17, indicates the final pressure upon the external clamping pressure heing relieved, see

FIG. 13,

The vertical lines indicating the pressure conditions in the material may as well represent the degree of axial expansion of the material. i. FIG. 1014 13 show the situation that the legs 40 are brought to project considerably from the rear side of the clamp beam 42 and are cut off as illustrated hy the dotted lines shown in FIG. 13. It should be emphasized, however, that it is hoth possihle and highly preferential to make use of hinders, which, as already discussed in connection with FIGS, 1-6 are preadapted to the production sao as to make leg cutting unnecessary.

FIG, 18 shows still a further self-locking binder, the legs of which are smooth, while in the receiver holes sharp internal edges 66 are provided as harbs that will but into the leg sides and thus prevent the legs from retraction from the holes.

Tt is essential that the binder legs do not draw the casing material into the receiver hnles, i.e. the material should he kept away from the hale ends until the leg ends have heen initially introduced intn the holes, and the legs and The holes should he disposed such that the inner sides of the legs engage the corresponding hole eders tightly, auch that the casing material cannot, during the huilding up of the pressure, intrude into the slots between the lege and the hole edges.

Ideally the heams should be very long, such that in its final shape the constriction area is almost extremely elongated, hut of course this would require the clamp heams to he very heavy for securing the required stiffness thereof. In practice the area will . nat need tan he more flat than corresponding to a suhstantially rectangular area with a side proportion of 1:8, normally even just to some 1:4, while a final proportion of 1:2 will mostly be too large for the achievement of an effective compaction and deformation of the entire cross sectional area.

Rased on the knowledge of the cross seclinnal aren and the type of the casing to he hound it is thus poasihle to preselect a suitahle hinder size, namely surh that the final constriction area, when deformation compressed e.g, some 20-40% or as required, should he held in a rectangular apening having a side proportion normally somewhere hetween 1:2.5 and 1:6, Herehy the binder width (length of the clamp beams) can he at least provisionally determined. Hereafter the length of the lege HA and 40 should be chosen such that the casing material in its loose condition (FIGS. 2, 9, 10) can he held within the U-memher 2,36 so as to allow the leg ends to he initially introduced into the holes 10,44 hefore a pressure huild-up starts in the casing material. The remaining parameter will he the thickness of the hlock heam 8,42, which should ideally be selected auch that the final clamping stage can be reached withnut the free leg ends projecting substantially from the rear side of the heam., Thus, the thickness of these heams can easily he selected hy a practical teat,

In practice it is of course important to control the clamping such that the constriction area finally assumes the required size or thickness between the clamp heams. Inasfar as the clamping pressure should he high ennugh to effect flowing of the material it is necessary ta either suddenly relieve the pressure when it has heen measured that the effective deformation e.g. of said 20- 40% has been nhtained, or, preferably, to positively limit the working stroke of the clamping tool means such that the clamping displacement of the clamp heams is hrought to stop when the predetermined final thickness of the constriction has heen reached. The tool equipment is easy to provide with suitable adjustable stop means for this purpose.

Thus, the applied «clamping pressure is not critical, when it is only high enough to effect the deformation. Narmally pressure of some 100 kp per mm nf a0 the effective width of the binder will be sufficient.

It has heen found possible to set up certain thearetical and empirical expressions far an acceptahle shape of the conctriction area and a reqiired mit jmum clamping pressure for ohtaining the super senl ing, haged on a thorough knowledge ofl all relevant material constants of the casing material and the binder, but it ie deemed nnneceasary in the present connection to treat this in more detail, inasfayr as it is possible, as ment toned, fn ascertain the rorrect condit ions hy adjustments based on practical {eata,

Recidea, it ia even helicved that therve will he experts still hetter qualified to treat the matter from

Aa physical caleulation point of view once it has now heen confirmed that hased on the considerations of the invention it ia, after all, pogaible to obtain t he desired result, Tn ather wnrds, when the result is known to he nhtainahle this will encourage the experts

Lo investigate the matter further, and it will he found, then, that it ig possihle to scientifically verify the invention and produce precscriptions for a successful use thereof in the various production situations for obtaining a sealing effect at least 10-100 times hetter than so far obtained.

As already mentioned it can he advantageous to provide for an exterior holding of the caonstvictian material ontaide the hinder for increasing the resistance against the axial displacement of the material, wherechy, particularly for a casing material of a low E-module, i.e. a relatively saft material, it will he possible to reduce hoth the required clamping pressure and the matual clamping dieplacement nf the opposed clamp beams. ereby the clamp beams may have

! reduced thickness and the axial dimension of the hinder may he kept low, such that a relatively cheap hinder can he used, This technique is illustrated schematically in FIGS. 19 and 20, where part-cylindrical clamp members AHR are chown to he forced against the casing constriction from npposite sides adjacent. hoth ends of the binder, The clamp members helong to the taal equipment of a machine as alsa having the required tools, represented hy arrows 60, for clamping together the clamp beams of the hinder. Care should he taken, of course, that the clamp members 58 do not compress the material sufficient to damage it. Even here, though the clamp memhers are shown ta be arched, they should preferably he planar elements operating in positions next to the respective hinder beams.

In FIGS. 21 and 22 it is chown that the mounting of the hinder on the ropstriction 18,46 may he effected hy moving the constriction along a slot 2 hetween opposed guiding plates 64, such plates heing provided hoth ahove and heneath the binding level. At the inlet end the slots 62 have widened portions 66 serving to narrow the constriction area by the introduction thereof. At the discharge ends of the slots 62 the U- memher 2 or 36 is held hy euitahle holding and hacking means AR such that the free leg ends thereaf project alightly over the onter ends of the guiding plates 64,

The constriction material is pushed along the slots hy means of the hlock heam 82 or 42, which, itself, is moved hy suitable driving means (not shown). Especially from the plan view of FIG. 292 it will he noted that with this arrangement it is ensured that the constrirtion material will he kept awav from the holes in the block beam at the moment of introduction nf the leg ends therein, while it is alan enasnred {hat the material ran be allowed to Fill ont the entire hinder opening already he fare ita initial compaction hy the further clamping movement of the hlock beam {ownrds the apposite heam 1,38. The hound area will he tTaterally removable and the operation vepeated, If clamp memhera KR (FINS. 19,20) are used they shonld he arveanged above and heneath the gniding plates 61, respectively.

Finally a few examples of providing a "super arpaled"” closing shanld he given:

EXAMPLE 1:

Casing material: BC-1, Crvavac, HSA. 2

Yield point: 450 kp/cm . 5 .

E-module: 3.600 kp/em

Thickness: 0.059 mm,

Peripheral length: 500 mm,

Fracture prolongation: 135%

Height of hinder: Af mm,

Effective width of hinder: 7 mm.

Effective thickness of hinder hefore deformation 4.2 mm,

Fffective thickneas of hinder after deformation 2.8 mm,

Clamping pressure applied: 700-800 kp (clamping stop at 2.8 mm).

FXAMPLE 2:

Casing material: pPT-1, Crvavacr, USA. 2

Yield point: 500 kp/em 2

E-module: A,600 kp/em

Thickness: 0.08 mm,

’ Peripheral length: 800 mm,

Friction coefficient (mensurecd): 0,20.

Fracture prolongation: 130%

Height of hinder: 7 mm.

A Fffective width of hinder: 12 mm.

Kflfoetbive thickness of hinder before deformation: 5.1 mm.

Fffective thickness of hinder after deformation: 2,5 nm,

Clamping pressure applied: 1.200 kp.

In this example a critical magnitude of the deformation is approached; and for increased security it conld he advisable tno make use of external clamping means according to FIGS. 19 and 20,

The examples are hased on the nominal values of the various characterigtics of the materials, and it has not heen taken into aceount that at leaat come of theae values may vary within inevitable tolerance limits,

Fxamples 3 and 4

Material: Polvester Polyethylene 2

Yield point: kp/om R00 130 2

F-module: kp/cm 13.200 2100

Thickness: mm 0.0175 0,085

Periphery: mm 400 200 2.5 Friction roeff.: 0,21 0,27

Fracture prolong.: 25% 410%

Binder:

Height mm 5 7

Width mm 4 16+ 20 Thickness: Start mm 1,75 4,75

Stop mm 1,45 2,6

Pressure kp: 400 700

In Example | the binder width may he rednced with the u=se of external clamps H8, FIGS. 19 and 20.

The hinder itself may consist of DELRIN or Aa similar hard material. ‘

Tn FIG. 23 is schematically shown an apparatus for mount ing the hinders according to the invent ion. This apparalus comprises a pa ir of appased, parallel heams 70 arranged substaniially horizontally, carried at their front. ends hv a rigidly =upporlied pival shaft i? and at their opposite ends heing height adjustable by means of a cylinder 74. At each sides of this pair of heams is arranged a stationary plate wmemher 76 having a vert. jeal frant edger portion TR. A constriction BO of a tubular packing oar casing may thus, as shown, he placed on or acroas the top edees of the beams 70 and against the edges TR, and thereafter the constriction may he arrested in this position hy means of a pressing element shown in dotted lines at 822, this element heing pivatable inwardly towards the constriction into a final position, in which it clamps the constriction against the edges 78 such that the horizontal thickness of the constriction will he less than the spacing between the legs 40 of the hinders used for binding the products of the particnlar produciion.

Underneath this clamping area of the constriction is arranged a piston 84, the top end of which is vertically movable hy means of a cylinder RA hetween fn lowered position, in which it is operable to receive from one side thereof a hinder U-member 36 as supplied from a magazine strip generally designated hy the reference numeral 88 of such wembers, and a raised . an position, in which the received U-member 36 is raised to a level, in which the bottom partion 38 of the fl-memher iz located just ahove the level of the top edges of the heams 70, vherehy the const riction 80 will be located hetween the opposed lege 40 of the U-member 36.

The cvlinder 86 can raise ita asanciated pistan rod 90 only nntil the Iatter ahnts a stationary abutment a7, while in the rod connection 94 te the piaton 14 there is inserted a unit 968 which is adinetahle to vary the effective length of the rod 91, anch that it is hereby possible to acenrately adjust the final ratased evel of the top end of the piston R1 as carrying the UU- member 36,

Overhead the constriction R0 is arranged a piston qR for hringing fn clamping heam 49 down anto the consirict ion, this piston being moved vertically hy means of a cvlinder 100. The piston 98 is raizable into a position above an inlet station generally designated hy the reference numeral 102 for clamping heams 42, these heam memhers having a ceptral cross slot 104 which . is engageable hy a downunrdly protruding hlade memher 1068 on the piston 98, wherehy fhe latter may carrvingly engage the heam member upon a support 108 heing retracted therefrom, wvhereafter the piston 98 will he operrahle to mave the heam memher 42 downwardly to engage wilh the npwardly protruding legs 40 of the U-memher 36 2h and ta effect a desived pressure against the top side of the constriction 80,

The appl ied pressure should he high enough to effect a Flowing of Ihe constriction material, and it ia important, therefore, that the final position of the piston 9] ahold nt he determined by the pressure applied, hit rather hy the final distance hetueen the apposed surfaces of the heam member 42 and the heam portion 22 af the U-member 26, To this end, nnee the aperative evel nf the piston 8:1 haa heen wel, [B bw important to Timit the dnunatrake of the piston AR an as to ascertain the required final thickness of the binding

Area, and the piston 98, therefore, i« provided with

Jaterally projecting portions 110, which are movahle against tat ionary, height adjustable stop means 112 (FIG. 24).

Thus, when the adjustable means 9h and 112 ave properly adjusted the compact ion and compression nf the congtriction area 0 will he stopper when needed, corresponding to the required deformation of t he constriction aren of producing a super araled closure.

Thereafter, when hindera according to FIGS. 1-4 are used, the wedge members 11 are actuated hy means of actuator rods 112 activated hy a cylinder 114.

The top edges of the horizontal heams 700 are neable as one part of the disclosed external clamping means (58, FIGS. 19-20), while the other part thereof may he arranger on the piston 98 an illuat rated hy apposed side plates 116 thereon, these plates having upper ontwardly hent portions 118, which are connected with a rigid piston portion 120 through a cylinder 122, wherehy the lower edges of the plates 116 may be lowered into positions resiliently clamping the conatriction material outside the hinder against the top edges nf the lower beams 70 for ohbtaining the result already described. The cylinders 122 may be pressurized an aa to exert the desired pressure independently of the final displacement of Ihe piston aR.

KB

Claims (7)

¥ 267 - 20719 Cc LATMS

1. A method af closing hose or hag shaped packings, primarily foodstuff packings, wherehy A constricted partion of the packing iz clamped by a ring shaped non-metallic clamp hinder caused to be narrowed about the constricted portion of the packing by a closing pressnre applied from appo<ite sides thereof and fixed in its shaped as attained when it is subjected to a final closing preasure, characterized in that the constricted partion of the packing is clamped hetween opposed smooth surface portions of suhstantially straight clamping heams of the non-metallic clamp binder «nas to he compacted into a final shape, in which the cemetricted portion of the packing ie cross-=ectionally oblong in =a laongitadinal direction of the suhatantially parallel clamping beams, preferably with a length of at Teast twice a distance hotween the clamping heams.

2. A method acearding to claim 1, wherehy hinder partiaonz interconnect ing respective ends nf the opposed clamping heams compriase at least at one end thereof a free leg memhetr on one clamping beam aperable io he received in n Tove lrable manner in aenverasl different positions in a receiver passage in the opposite clamping heam, the method heing completed with t he free leg memhe rr end Pe ft uncut and vel in Aa non-tearing condition, either hy being entirely housed inside <aid receiver passage or, il projecting substantially heyond a rear end of the receiver passage, hy having a smoothly rounded end portion, an 3, A method according tao claim 1, particularly far obtaining a very of fective seating of a constricted nd

. ° 0 G na | ( . 26719 plastic casing material, wherehy the hinder is celect ord and the constriction diepnced in ane oa manner that nn the said final shape of the hinder the hinder opening i= entirely fFitlied nut by the const viection material, ied ronstrict ion malevrial he ing anbhiect od tn =n h a compact ion preagsure hetwern the clamping beams that in each and every pari of the final constriction aren t he plastic material is effectively avially displaced to a degree helow ruptuare prolongat ion and thas acaiimes an averall axially expanded condition.

4. A method acearding to claim 3, wherehy the applied pressure ic steadily sufficient {nr deform the canstriction material and the opposed clamping heamz are canced to he mechanically stopped al auch a wmutnal distance, which corresponds to the effective distance hetween the clamping heams heing of a size required for enanring the overall axial evpansion nf the material,

he.

A melhind accarding to claim 4, wherehy, in : arder to counteract a rupture prolongation of the axially expanding material with the nce of a hinder of relatively small axial length, the cancstricted material portions just oul=ide the apposed ends of the binder are merhanically clamped between clamp tool memhere and thus axially stabilized while the clamping heam ave forced 24 into their final positions, f, A clamp hinder for closing hose or hag shaped packings hy the method claimed in one of claim | oor 3, the clamp hinder consisting ramen! inlly nf a non- metallic material and comprising two opposed clamping portions and connector means t hevrehelween for confining, together with the elamping portions, an annntar hinder atructure, in which at Jeast one of said connector means ie operable to interlock the associnted parts nf {he clamping portions wilh a mutual spacing Lherehelween Hpon t he: clamping porlionas heing forced against a conatricted packing portion from opposite =iides theveaof, characterized in {that the apposed clamping portions are conal tuted hy anhatantially straight clamping beams and that the connector means are arranged =o as to enable the hinder fo he closed abiont a non-campacted conatrict ion aves and enable the olamping heama toy he Forcnd together to compreze the constriction aren inta a final shape, in which the heams are snhgstantially parallel and spaced from each other at a apacing leas than the spacing hetween the respective connector means,

7. A hinder according to claim A, in which one of t he clamping heams ia at each ened provided with a ITaterally protrading Ves member co as to form a rigid U- memhe rr with a strajicht haottom portion, while the nuter clamping heam is provided with two individual holes for receiving the leg members, arresting means he ing provided in connection with each leg memher and/or hole operable ta lock the les memherae agains! retraction from the hales.

a. A hinder according to claim 7, in which the arrest ing means comprise wedge memhers projecting from the free ends of the leg members =o as to he introducahle into the holes along with the leg ends and tao he repressable from the opposite end of the holes for widening the cross aectional area of the leg ends sufficiently ten effect a retraction locking of the leg memher in the hale, a6

Ce v 26719 (19 oS 9. A machine for mounting a clamp hinder on a constricted packing portion in accordance with the method claimed in one af claims 1, 3 ov 5, the machine comprising me an < far forcing apposed hinder portions against the constricted portion of { he packing and characterized in Turlher compriaing clamping tool means operable to clamp the conet ricted material juat ont aide apposed avial ends of the clamp hinder for atahiliving the material against excessive axial diaplacement in an aren surrounded hy the clamp hinder.

Tnvnntors: FRTEK MADSEN FIEMMING KROMAN