Note: Descriptions are shown in the official language in which they were submitted.
~C~7 777 3
Reference is had t~ the applicant ' s copending
applicati~n Serial No. 242,111, filed December 17, 1975.
This invention relates to a ~vel packsge of
tubular materi~l, and more p~rticularly ~o ~ length of
c~mpres~ed, pleated fle~lble tubin~ retalned withLn ~n
ela6tlc sheathing materlsl to form a ~e'L:E-su6taining
tube thereof.
Fle~ble tubing ~terial such a~ fle~c~ble
plast~cs ~ e~astomers 9 p~per ~ f~bric and the like heretc>- :
fore have ~een pr~vided either in the form of ~hort piece~
th~t can be easily opened and filled a~ packages or wou~d
in flattened form on suitable ~p~oL8 or cores for torage.
When tubuLar material hafi been provided in the orm of a
flat~ened tube wound on a spool or core~ it ha~ been
generally used by unw~nding rom t~e core and openlng and
filling in discrete ~eg~ent8.
In the mea~ packi~g ~n*u~try, ~ynthetic sausage
casings " whlch are a specialized type of ~ ble tubing
~terial, ranging ~n length~ of fr~m 40 to 160 feet or
~ore, are prepared in a ple~ted ~Lnd compre~0d or shirred
fc~r~ of the or~er of a few inche~ $n length,, The COD-
. 2t) preQsed length o~ ular ca~ing iB filled ~r placing on
a ~tuffing horn tl~r~uRh ~h~ch a D~at ~lei~n is extruded
- ~o :IEill ~he c:~eing to 1~CB fully egi:OEded lengt~l.
. The ~h~rring app~r8~u~ ~d prl~t:eS~e8 ~?idely u~ed
~n 'che ~u6age ca~ing ar~ ve ~een generally ~ und mo8t
.: ~ui~cable for u~e ~l~h ~mall diam~0r (i.e., h~ving a di-
ame~er o ab~t 12 mm ~o 40 ~n~ ar~cifici~l ~bular c~
~uch a~ ~ed in the pr~dw~ of fr~nkfurter~e ~d
p~rticularl9 CAsiDlg for~d o~ regenera~e~d c:eïlulc~
.. .. .
.
' ~ ~ 7 7 ~ 7 3 9499
Cellulosic ca~ings of intermediate or larger size with
di~meter~ greater than about 40 mml ei~her reinforced wi~h
ibrous material or no~, h~ve grea~er wall ~hicknees or
other characteristics tha~ limi~ the compactlng and in~er-
locking of the pleated tubing wall~. As a result, com~
pressed 10ngths of such pleated tubular casing do no~ maln-
tain ~he integrity required to be self-sustaining and the
compressed tube~ tend to break and the pleat~ ~eparate.
In one widely used prior art technique to over-
c~me ~hi~ disadvantage, the compressed length of plea~edtubing made from large diametcr tubing is provided with a
support core, generally in the form of a rigid tube of
plastic material, inserted into the bore of the compressed
leng~h of pleated tu~ing immediately after ~he compres~ion
step. Separation of the compre~ed pleat6 is prevented by
a pin or peg extending transversely through the w~lls of
the support tube at both extremitles thereof~ restr~ining
the endwi~e expan~ion of the co~pressed ~ubing.
The core tube and peg arrangement is relatively ex-
pensi~e. Moreover, the arrangement does not permit readyplacem2nt Dn a s~ufing honn without additional time-
consuming manipula~ions by the stuf~er operator~
Other technique~ for maintalning the integrity of a
co~pres~ed ~trand of tubular ca~ing h2~e been ~hown in ~he
.; patent literature and ~pecific reference is m~de to ~. S.
Patent ~08. 3,528,825 ~o Dough~y and 3~6393130 to E~chin.
H~wever9 there is ~till a demand for a ~ethod of
~oring long le~gths o ubular material tha~ is simple
. 3
.
~ 9499
77'73
and economical in both time and material and which permits
continuous filling of the tubing. A particularly desirable
technique would be one that was suitable for use with a
wide variety of different types of tubular materials
enabling them to be readily and continuously filled in
packaging and the like applications.
In aecordan~e with the present in~ention, there
is provided a unique self-sustaining length of flexible,
thin-walled tubular material comprising a length of pleated
and compressed flexible, thin-walled tubular material having
a bore extending therethrough and a tubular elastic sheath-
ing material stretched and tightly drawn about the periphery
o said length of compressed tubular material and down
about at least a portion of the terminal pleats at each
extremity thereof, said sheathing retaining the c~mpressed,
pleated thin-wall tublng in a self-sustaining length thereof
without restriating the bore therethrough.
The invention also includes a method for preparing
a substantially self-sustaining length of pleated and
compressed flexible tubular material which comprlses pro-
; viding a length of pleated and compressed flexible, thin-
walled tubular material supported in a longitudinally
compressed state about a mandrel, providing a length of
tubular elastic sheathin,g ma~erial having a diameter smaller ,
- than the outer diameter of said eompressed tubular mat rial,
; and preferably that is longer than said length of cbmpressed
tubular ma~erial, stretching at least a por~ion of sa:id
tubular sheathing material and positioning the stretched
~ 49
1~77773
portion thereof about the periphery of a length of compressed,
pleated tubular material with the ends of said sheathing
material extending beyond the ends of saicl compressed tubular
material, releasing the stretching forces on said sheathing
material and permitting the stretched sheathing material to
contract about the periphery of said lengt:h of compressed
tubular material and down about at least a portion of the
terminal pleats thereof whereby said length of compressed,
pleated tubular material is retained totally within said
sheathing material without restricting the`bore therethrough,
and then removing said sheathed length of pleate.d and
compressed, tubular material from about the supporting
mandrel.
In a preferred embodiment, a tubular sheathing
material that is longer than the length of compressed
pleated tubular material ls circumferentially stretched -
only along a portion of its length and the unstretched
portion aids in positioning and locating the ~tretGhed
portion of the sheathing material about the length of com-
20 pressed tubular material.
It is important that ~he sheathing material aboutthe periphery and ends of the compressed tubular material
be under sufficient ~ension to maintain the longitudinal
compression on the compressed, pleated tubing and thereby
the mechaniçal integrity required to produce a substantially,
self-sustaining length thereof.
An advantageous aspect of the shea~hed length
of compressed tubular material of the pre~ent invention
is that a considerable length of thin-walled flexible
tubular material is made available in a relativel~ small
'' ' ' ' :
.
77773 9499
package that may be readily handled during ~torage
and ~hipping wi~hout prema~ure ~epara~ion o the plest~
and the configuration ~hereof lends iltself to mo~nting on
various ~tuffing mean~ for continu~us filling 3f the
tubular material without undue fur~her man~pulation.
Further, in the ca~ of ~ubular n~terials ~uch
as cellulo~ic food ca~ings whieh r~quire ~rea~men~ ~uch
a~ soaking in wa~cer to improve stuing characteri3tic~,
t~e soaking operation may be oarried out without removing
10 ~he sheathing material, and the ~heathing ma~cerial will
contain the expansion in length of ~he tu~ular ca~ing due
to increased moisture conten~, permi~ting the moisl:ened
sticlc to be easily m~unted on various type~ of ~tuffing
horns .
The article and method of the present illYen~ion
will become apparent from the ~ollowing description thereof
when consider~d together wi~ch ~he accomparlying drawing
which is set forth a~ being e~cemplary of various embodLments
o~ the pre~ent inv~ntion and nolt intendedD in any w y to
20 be limita~ive thereof and wherein the 801e figure i~ a
side elevation view, partially in ~ection, of an e$emplary
~mbodiment of a self-~u~taining length of pleated and
c~mpres~ed thi~-walled, flexible ~ubular ma~erial of the
illvelltiorl.
.
6.
~077773 9499
~ Referring now ~o the drawing, there is shown in
the figure a len~h 10 of pleated and compr~ssed thin-
walled, flexible tubing having ~ bore 11 extending
therethrough. The length of compressed thin-walled,
flexible tubing 10 is contained within a tubular elastic
sheathing material 12 that is ~tretch~d and ~ightly drawn
about ~he periphery of said compressed length of tu~ular
materlal and down abou~ at lea~t a portion of the terminal
plea~s 13 and 14 at ~he extremities thereof, preerably
without restricting ~he bore therethrough. The ends 15
and 16 of the sheathing material 12 extending beyond ~he
e$~remities of the compressed tubing 10 are in a relaxed
and untensioned state, retaining the terminal pleat~ of
: the compres~ed, pleated tubular material th¢rein thereby
re~aining the entire length in a compre~ed sta~e and main-
taining the degree of compression on ~he pleats sub~tantially
as originally imposed thereon ~o form a self-~u~taining
length thereof.
A wide v~riety of tubular ma~erials m~y be employed ~;
in the preparation of the self-~ustaining length of c~m-
pressed, pleated tubular material of the present invention.
Suitable tubular ma~erial may be a~y thin-w~lled, ~: :
flexible tubing that may be prepared in a con~inuou~ length
of, for example, 40 or more fee~, and tha~ is flexible yet
~rong enough to wi~hstand rapid olding and a high degree
of compression when folded. Typical ~aterial~ are thin~
walled9 ~lexible thenmopla~tic tu~lng such as may be
prepared rom polyethylene and other polyolefins~
7.
'
; 1 ~7 7 ~ ~ 3 94g9
polyvinylidene chloride 9 polyvinylchloride 7 polyesters
and the like, and regenerated cellulosic tu~ng including
ibrous web reinforced ~ubing, such as intermediate and
large ~ize tubular fibrous ~susage casing.
I~ has be~n found that apparatu~ and processes
well known in the food casing art for shirring tubular
cellulo~ic food casing such a~, for example, disclo8ed in
U. S. Patent ~os. 2,983,949 and 29984,574 to Matecki, may
be em~loyed in th~ preparati~n of the plea~ed ~nd com-
pre~ged tubular materials o the present inYention w~reinc~mpres~ion ratios of at lea~t about 40:1 and up ~o about
100:1 or even grea~er may be ob~ained.
Tubular ela~tic material constitut~ng the sheath-
ing material of the present i~ven~ion may be prepared~from
any one oi a wide variety of well known pla~tic or
`- elastomeric material~ which are elastic~ ~.e., i8 capable
o being ~tretched and then ~ubstan~ially recovering its`
original size and shape when ~tres~ is removed. For ex~mple~
thermopla~ic polymers such as polyvinylchloride9 polyvinyl-
; 20 idene chloride, polyethylene and ot~er polyolefin~ formu-
lated to e~hibit suitabl~ elastic propert~es as more ex~en-
slvely di~cussed hereinafter may be suitable or preparing
the fiheathing material of the present in~en~ionO Also
uitable may be elas~omerlc ma~erial~ such as nntural
rubber, polychloroprene 9 polyurethane, polybutadiene-
-~ s~yrene copolymers and the like.
In gener~l~ 8ui~bl~ tubular~ ela~ic ~hea~hing
material may be ~eamle~s or ~eam~d tubing and may be pr~pared
~'
; 8.
~', . .
9499
~ ~ 7 7 7 7 ~
as individual discrete lengths or cut r~m continuous
leng~hs of tubing. The ela~tic tubi~g of this invention
~hould be capable of being uniorm1y ~rans~ersely circu~-
ferentially expanded at lea~t 75/O witho~t tearing or rup-
turing and ~hould e~hibit a "penmanent ~et" no~ greater
than about 10~/.. Relatlvely high ~effsile modulus properties
st low elongation, i.e~ the ~tres~ re~q~ired to ~tretch
the material 30/0 to 9C~/., is also desirable to ma~ntain the
mechanical integrity of the conpres~ed leng~h of pleated
tubular material and retain the ~erminal pleats within the
shea~hing material yet sh~uld not ca~se distortion of the
pleated tubing or the general con~iguration of the compressed
tubin~. The el~stic sheathing material may be perforated
to provide holes about the periphery o the ~heathed9 com~
pressed, pleated tubing when, for exampLe9 Lt may be desired
to provide means or the ready soaking with wa~er o a
compressed pleated tubing such a~ fibrou~ ~ausage ca~ing.
The self-au~taining leng~h of compressed plea~ed
tubing of the present invention may be prepared in coniunc-
tion with the apparatu~ u~ed ~o form the pleated and com-
pre~sed length of thin-walle~, flexible tubing or completely
separate therefrom.
A typical method for preparing ~he self sustaining
length of c~mpres~ed, pleated tu~lar material of the
pre~ent invention may involve supporting a lengt~ of com-
pressed9 pleated tubing on a mandrel while main~ainlng a
longitudinal compression on ~he pleated tubing to prevent
prem~ure separation thereof~ The suppor~ mandrel for the
9499
'77773
compressed tubing may be the mandrel over which the tubing
was advanced during the pleating and c~mpaction thereof
or may be any suitable support mandrel means about which
the compressed, pleated tubing may be arranged having
associated therewith means to maintain the desired longi-
tudinal compression on the pleated tubing. While the
amount of compression used is not critical, it should be
sufficient to purge as much air as possible from within the
pleated tubular material to establish the highest possible
; 10 apparent density within the deslred length of compressed,
pleated tubular material.
A length of elastic tubular sheathing material
having two open ends is then uniformly transversely circum-
ferentially stretched and the stretched sheathing material
is positioned about the lo~gitudinally compressed length
of pleated tubing with the ends of the tubular sheathing
material extending beyond the ends of the compressed tubing.
The tubular shea~hing material may be uniformly circum-
ferentially stretched u~ing means well known in the art.
The ends of the shea~hing material extending beyond the
ends of the compressed length of tubing contract and are
drawn down about the terminal pleats at the extremities of
the compressedg pleated tubing whereby the entire length of
said pleated tubing is retained within the ~ubulax sheathlng
material. The sheathed compressed, pleated tubing may then
be removed from about the supporting mandrel.
It is essential that ~he elastic tubula~ sheathing
~ material is long enough or can be stretched to contain the
:, 10.
9499
~77~73
compressed length of tubing to be retained and, fur*her,
that the unstretched diameter of elastic tubular sheathing
is smaller than the outer diamet~r of the compressed,
pleated tubing. It is also generally preferred that the
unstretched diameter of the tubular sheathing material is
large enough so that it will not restrict the bore of ~he
compressed, pleated tubing retained therein.
In general, the original unstretched diameter of
the tubular sheathing material should be at least about 10%
and preferably at least about 20% smaller than the outer
diameter of the compressed, pleated tubing to be sheathed.
Tubular sheathing prepared from suitable elastic materials
as herein described, that exhibits "permanent set" proper-
ties less than about 10% after being s~retched from about
30% to 90%, should, therefore, recover after belng stretched
an amount sufficient so that the ends thereof extending ~ ~ -
beyond the extremities of the c~mpre~sed, pleated tubing
will be drawn down about the terminal pleats of the com-
pressed tubing to retain the entire length thereof withln
the sheathing material. I~ will be apparent to those
skilled in the art that the diameter of the elastic tubular
sheathing material actually required to retain a compressed
length of pleated tubular material will depend on the type
of pleated tubing that is to be retained and the degree of
compression required to maintain the mechanical integrity
or desired length thereof. The actual type and dimen~ions
of ~u~ular sheathing material can be readily determined
in accordance with the teaching herein for the wide variety
77773 9499
of thin-walled, flexible tubing that may be employe~ in
the preparation of the self-suataining length oP~compressed,
plea~ed tubular material of ~he pre~enlt i~entlon.
Alternati~ely9 in accordance! wi~h the pre~ent
lnven~lon, a c~mpre~sed, pleated tubing supported on a
mandrel is maintained under longitudinal compre8sl~n to
maintain it~ desired length. A tubular 6heathing materi~l,
as herein described, that i5 longer than ~he compres~ed
tublng to be ~heathed i8 uniformly, transversely circum-
; 10 ferentiaLly stretched over a portion of its length and
the compre~sed, pleated tubing i8 in~erted in~o ~he
- ~tre~ched sheathing material un~il contacting the portion
of ~he~thing material that had not been stretched. The
mean~ employed for inserting the compre8sed tubing in~o
the stretched 8hea~hing material may also be used to exert
a final longitudinal compre3sion on the compr~s~ed tubing
before or after withdrawing the stretching force~ from
the sheathing materi~l. The stretching force~ m~y then
be withdrawn from the sheathing material, permi~ting the
stretched portion thereof to contrast about the compre~8ed
length o pleated tubing to retain ~ therein. The
sheathed~ compres~ed ler~g~h of pleated ~u~ing, when remo~red
rom about the supporting mandrel, i8 ~alf-sustaining ~Lnd
maintain3 itB int~grity during handling thereof.
In accordaT~ce with the practice o~ the presen~
invention, there is prepared a self-~us~aining letlg~h of
compres~ed, pleated T~ubul~r materi~l wh@rein a long
contin~ous length of thin-walled" flexible tu~ing is
' . z~.
~1~77~73
provided in a ~ubstantially ~horter leng~h ~hat may be readily
handled during storage and shipping and may be continuously
filled using automatic stuffing equipment.
Elastic tubular sheathing materials suitable for use
in accordance with the practice of the invention are, in
general, capable of being stretched longitudinally concurrently
as they are stretched circumferentially. In an alternate
embodiment of the present invention, there is prepared a
length of compressed pleated tubular material supported on
a mandrel and maintained under longitudinal compression to a
predetermined length~ An elastic tubular sheathing material,
as herein described, i9 provided of a length equal to or
shorter than a desired predetermined length o~ compressed
pleated ~ubular material. Said elas~ic material is uniformly,
transversely circumferentially stretched over a portion of
its length by stretching means, and a first end of the com-
pressed pleated tubing is inserted into the stretched
sheathing material until contacting a first end por~ion of
~heathing material that had not been stretched. A final
longitudinal compression is exerted on the compre~sed,pleated
tubing to progressively remove the sheath from the stretching
mean~, and longitudinally stretch the sheathing material until
the second end thereof extends beyond the second end of 3aid
compressed tubing to provide an amount of sheathing material
sufficien~ to contract down about a~ least a portion of the
terminal pleats of the compressed length of pleated tub~ng
` and retain it therein.
The invention is further illustra~ed by the ~ollowing
examples which are not to be construed ~8 llmitative since various
modifications can be made within the tèac~ings di3closed herein.
12a.
. ~ ' , " . :
~L0777~3 ~499
EXAMPLE 1
Food casing "~hirring apparatus" as disclosed
in U. S. Patents 2,g83,949 and ~,984,574 was employed
in this example.
A 27.5 meter length of thin-walled, flexible
tubular material prepared f ~m polyvinylidene chloride
polymer resin was ad~anced about a hollow "shirrlng"
mandrel through the "~hirring passage'l of a "shirring
machine" and the pl~ated tubu~ar material was longitudinally
compressed on the m~ndrel to a length of about 26 cm. The
tubing employed had a flat width of about 19.7 cm.and a
wall thickness about 0. 056 nm~
Uslng the stretching apparatus disclosed in
U. S. Patent 2,884,328, a 46 cm.long segment of an elastic,
flexible, tubular material prepared from polyvinylchloride
re~in commerclally available under the trademark "VISTEN"
was transversely circumferentially stretched about 40~b
over a sub~tantial portion of its length and the stretched
tubing ~as positioned over ~he compressed length of pleat~d
tubing with the ends thereof extending beyond ~he ends of
the compresæed tubing~ The elaætic tubing had a flat width
of about 14 c~ and a wall thickness of about 0.046 mm.
The stretching de~ice was removed from the tubular
elastie material and ~he elastic tubing eontracted about the
c~mpres~ed len~th o~ pleated ~u~ing totally retaining the
pleated tubing thereln,
F~ve more 27.5 meter length sample~ of the thin-
walled polyvinylidene chloride tubular material of this
13.
~ 77773 9499
example were pleated, c~mpressed and ~hen sheathed as
~escribed above.
The six samples of shea~hed3 compressed, pleated
tubular material were measured and fo~nd to range -in
length from about 33 cm. to 39.4 cm~ The internal or bore
diameter of the shea~hed t~bular mater~l ranged rom
5.1 cm~ to 5.7 cm. and the external diame~er ~rom 13.6 cm.
~o 14.6 cm. After removal from the "shirring" mandrel~
each of the lengths of sheathed~ csmpressed, pleated
tubular material was self-sustaining and no premature
separation of the pleats occurred during handling. The
internal bore through the compressedg plea~ed tubing was
substantially straight and unres~ricted. Water pressure
testing of the plea~ed tubular materi~l showed that no
rupturing or formation o~ pin-hole~ re~ulted from the
~ plea~ing and compression operations~
: EXAMPLE ~
The apparatus and procedure~ of Example 1 were
used for processing 23 me~er lengths of variou~ types o
20 thin-walled, flexible tubular materials into pleated ant
compressed lengths thereof about a "~hirring" mandrel.
The compression force used to longitudinally compress the
pleated tubing about ~he mandrel was the same for all the
samples.
The elastic tubular sheathlng mater~al of ~am-
ple 1 was used in this example. Four different diameter
tubular shea~hing materials were used wi~h each of the
various samples of compressed, p~eatad tubing Df this
~: 14.
- , - .
~ ~ ~ 7 ~ ~ 3 9499
example and the procedure of Example 1 was used to sheath
the compressed, pleated ~ubing samples of this example.
The types of thin-walled, flexible tubular
material used to form the compr~ssed" pleated tubing and
various characteri~ics of the sheathed, compres~ed lengths
formed therefrom are summarized in Table I below.
Each of the samples of the example was self-
sustaining, had an unrestricted bore and exhibited no
premature separation of the ~ompressed pleats during
handling. Deflection of the Sample L sheathed tubing
may be greater than desired for ready in~tallation on
a stuffing means but would not be totally unsuitable.
15.
9499
07~73
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16 ~
" ~ ~7 ~ 7 7 3 9499
.
EXAMPLE 3
Using the apparatus and procedures of Example 1,
23 meter lengths of a 15.5 cmO flat width(9.9 cm diame~er)
tubular fibrous food casing having a moi~ture content of
about 14% were pleated and compressed and then sheathed
with the elastic tubular sheathing ma~:erial of Example 1.
Several diameters of sheathing material were used, The
sheathed, sel-sustaining lengths of compressed ~ubular
material were immersed in water or various periods of
time and the effects of water immersion are summarized
ln Table Il below.
Each of the samples prepared was a self-sustaining
length of the compressed fibrous tubular cas-lng that
exhibited no premature separation of the pleated tubing
; during handling ~hereo0 After the water immersion tests3
.~ each ~ample of sheathed tubing maintained its self
su~taining characteri~tics and in no instance did any of
the pleated casing exude from wi~hin ~he sheathing material.
Further, the shea~hed length~ of pleated tubular casing
could be mounted on the stuffing horn of a food stuffing
machine and continuously stuffed without the need for
removing the ~heathing ma~erial prior to stuffing.
~3777'73 9499
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18.
7 7 ~ 3 9499
EXAM2LE 4
~ sing the apparatus and procedures of Exa~ple 1,
three 23 meter long samples of the thin-walled, flexible
tubular material of Example 1 of ~hree different diameters
are pleated and compressed and then shea~hed with the
elastic tubular sheathing ma~erial of Example 1.
Characteristics of the self-sustaining lengths
of compressed tubular material are summarized in
Table III.
19.
~`" 9499
~7'7773
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