Interlocked continuous webs

Continuous superimposed webs are interlocked together along opposite marginal edges by sets of superimposed tongues provided in the webs which interengage to effect an interlock. Each set includes at least a pair of superimposed tongues disposed along a line forming an angle with an adjacent marginal edge so that one of the tongues is staggered relative to the other in the direction of feed of the webs through a web processing machine. Thus, during separation of the plies in the direction of feed the forwardmost superimposed tongues are separated before the rearwardmost tongues thereby avoiding simultaneous separation of the tongues and decreasing the resistance offered by the tongues upon ply separation.

BACKGROUND OF THE INVENTION 
This invention relates generally to interlocked continuous webs, and more 
particularly to the provision of sets of inter-engaging tongues staggered 
along at least a marginal edge of the webs for interlocking them together 
and for facilitating an easier separation of the plies. 
For the purpose of releasably interlocking continuous super-imposed webs 
together, interengaging superimposed tongues have been provided in such 
webs for preventing both longitudinal and transverse relative shifting of 
the webs while at the same time permitting the webs to be separated or 
peeled apart during decollating. Such tongues may be spaced along one or 
both marginal edges of the webs and are provided by punching or slitting 
through the webs to form substantially U-cuts forming tongues integrally 
attached to the webs and having free ends and side edges provided by the 
deviating slits. The tongues may likewise be formed by substantially 
H-shaped cuts. 
At each spaced location along the marginal edge or edges, one or more of 
such superimposed tongues may be provided depending on the holding 
strength required for the number of webs to be interlocked together. 
However, where more than one of such superimposed tongues are present at 
each spaced location, they typically lie along a line perpendicular to 
their adjacent marginal edge. Consequently, when such webs are peeled 
apart during a web decollating operation, the interengaging tongues 
between webs at each location along the marginal edges unlock or disengage 
simultaneously as the webs of the assembly are decollated. Hence, the 
decollating operation is not smooth by reason of a "tug" or a "snag" 
experienced each time a set of the laterally disposed sets of tongues are 
peeled apart. In other words, the resistance offered by the two or more 
interengaging tongues at the spaced locations along the marginal edges is 
sufficiently great as to affect the smooth decollating operation of the 
webs. 
SUMMARY OF THE INVENTION 
Interlocking tongues are disposed for securing together a plurality of 
superimposed webs of a continuous web assembly in such a manner that 
during decollating the strong resistance offered by a plurality of such 
tongues at spaced locations along the marginal edges is avoided without 
affecting the holding power offered by such plurality of tongues in 
maintaining the webs effectively secured together. This is accomplished by 
staggering superimposed tongues in each spaced set so that adjacent 
tongues of each set lie forwardly of one another in the direction of feed 
of the assembly through a web processing machine. The superimposed 
interlocking tongues of each set lie along lines disposed at angles to 
their adjacent marginal edge so that only a single one of the tongues of 
each set will disengage during the web decollating operation, with such 
disengagement occurring before the next adjacent tongues disengage. The 
interlocking tongues thus behave similarly as single tongues at each 
spaced location since the set of a plurality of tongues is staggered 
relative to one another. A smooth decollating operation is therefore 
assured for the webs.

DETAILED DESCRIPTION OF THE INVENTION 
Turning now to the drawings wherein like reference characters refer to like 
and corresponding parts throughout the several views, a continuous web 
assembly is generally designated 10 and comprises a plurality of 
superimposed webs 11 to 14 interlocked together by means of interengaging 
locking tongues 15 to 18 respectively provided in the overlying webs. 
Spaced feed holes 19 are provided along opposite marginal edges of the web 
assembly for engaging correspondingly spaced feed pins of typical tractor 
feed devices provided for feeding the web assembly in a direction of the 
arrow shown in FIG. 1 through a web processing machine. Of course, the 
feed holes may be provided along only one marginal edge for cooperation 
with a single feed device. And, each of the webs of assembly 10 is 
provided with superimposed transverse lines 21 of weakening for fan 
folding the assembly into a zigzag pack and for ultimately separating the 
assembly into individual units when burst along these transverse lines. 
Sets generally designated 22 of locking tongues are equally spaced (see 
FIG. 1) along both marginal edges of the assembly and, for convenience, 
these sets may be located between adjacent feed holes as shown. 
The interengaging tongues of each set, as clearly shown in FIG. 2, are 
transversely spaced from one another and are staggered in the direction of 
feed to form an echelon arrangement of the three locking tongues of each 
set. (The showing of three tongues per set is only exemplary. Two or four 
tongues per set may otherwise be provided.) Hence, interlocking tongues 
generally designated T of each set lie forwardly in the direction of feed 
of the web assembly relative to adjacent interlocking tongues generally 
designated T.sub.1, and tongues T.sub.1 in turn lie forwardly of adjacent 
interlocking tongues generally designated T.sub.2. These tongues of a 
typical set are graphically illustrated in FIG. 2 at opposite marginal 
edges of the assembly, and only the cuts forming the tongues are shown in 
the interest of clearly illustrating the particular disposition of tongues 
T, T.sub.1 and T.sub.2 of each set. Of course, the sets of tongues may be 
spaced along only one marginal edge of the assembly, if desired. 
A punch device of some standard design may be used in forming each of the 
tongues by providing superimposed U-cuts 23 from a side of the assembly so 
as to define tongues 15 to 18 having free leading ends 24 and trailing 
ends 25 integral with their respective webs. As clearly shown, the tongues 
of each set lie along lines L disposed at angles to their adjacent 
marginal edges, with trailing ends 25 of tongues T lying laterally of 
leading ends 24 of tongues T.sub.1. And, trailing ends 25 of tongues 
T.sub.1 lie laterally of leading ends 24 of tongues T.sub.2. It should be 
pointed out, however, that the adjacent tongues of each set may slightly 
overlap, or that the adjacent tongues of each set may be slightly spaced 
from one another in the direction of feed so as to form slight gaps 
therebetween. 
FIGS. 3a, 3b and 3c illustrate the sequential unlocking of the tongues at 
T, T.sub.1 and T.sub.2 upon decollating or the peeling apart of web 11 as 
the assembly is moved in the direction of feed during a decollating 
operation. A detailed description of this operation will follow 
hereinafter. 
Before decollating, all the tongues 15 to 18 at each of T, T.sub.1 and 
T.sub.2 are respectively interengaged, as typically shown at T.sub.1 and 
T.sub.2 in FIG. 3a, as they are deflected outwardly of one side of the web 
assembly through cuts 23 so as to interengage as well as to engage in the 
adjacent apertures formed by the cuts so as to attach the webs relative to 
one another in the assembly. The particular formation of these tongues and 
the manner in which they serve to interlock superimposed webs together is 
by itself known in the art and is typically shown in U.S. Pat. No. 
2,246,065. 
The arrangement of tongues T, T.sub.1 and T.sub.2 of each set 22 of tongues 
as aforedescribed is likewise typical for a plurality of tongues fewer or 
more than the three per set 22 illustrated in the present drawings. Hence, 
if only two tongues T and T.sub.1 per set are found necessary to 
releasably interlock superimposed webs together, they would be arranged 
along sloping lines L for each set. And, if four tongues per set are 
required for a given number of superimposed webs, they too would be 
arranged along sloping lines L for each set in an echelon fashion as shown 
in FIGS. 1 and 2. The number of tongues T provided for each set is 
determined by the holding power needed for interlocking a predetermined 
number of webs together in the assembly. 
FIGS. 3a, 3b and 3c illustrate various stages of web separation during a 
web decollating operation. However, for the purpose of clarity only top 
web 11 is shown in the process of being separated or peeled apart from the 
remaining webs of the assembly. These remaining webs may be separated from 
one another at the time web 11 is separated, or they may be separated at 
some other stage of the decollating operation. Upon decollating either 
manually or with the use of a decollator of any well known type, adjacent 
webs are moved further apart as the assembly is moved in the direction of 
the arrow shown in FIG. 3a. A typical set 22 of tongues is shown in this 
Figure wherein tongues 15 of those shown at T near opposite marginal edges 
of the assembly disengage upon web separation while the remaining tongues 
T.sub.1 and T.sub.2 remain interengaged momentarily. Upon further web 
separation tongues 15 at T.sub.1 are moved apart for disengagement as 
illustrated in FIGS. 3b; and, upon still further web separation tongues 15 
at T.sub.2 become separated as shown in FIG. 3c. It can be therefore seen 
that single tongues of each set encountered during web separation are 
disengaged at opposite marginal edges of the web assembly, with the 
remaining tongues in such sets disengaging sequentially upon web 
separation. The "snags" or "tugs" normally experienced during tongue 
disengagement for those transversely or laterally disposed tongues in each 
set as in the prior art are avoided with the present invention since 
tongues T disengage before tongues T.sub.1 which disengage before tongues 
T.sub.2 thereby each offering a disengaging resistance equal only to that 
of a single tongue during decollation. However, the holding power created 
by the use of several tongues arranged in the form of an echelon is 
comparable to a like number of tongues arranged transversely of the web. A 
simple and smooth decollating operation is thereby assured with the 
present arrangement. 
An alternative form of tongue formation is shown in FIG. 4 wherein tongues 
15a to 18a and 15b to 18b are formed by substantially H-shaped cuts made 
at one side of the assembly by a suitable punch device. 
Obviously, many modifications and variations of the present invention are 
made possible in the light of the above teachings. It is therefore to be 
understood that within the scope of the appended claims, the invention may 
be practiced otherwise than as specifically described.