Web loading and feeding system

A web loading and feeding system comprises an elongated web and a web loading and feeding machine. The web is fed longitudinally of itself through the machine by a pair of drive sprockets having pins which cooperate with holes in side edge portion of the web. The hole arrangement in the web and the pin arrangement on the sprockets readily enable a machine operator to visually determine how to properly load the web onto the sprockets.

BACKGROUND OF THE INVENTION 
The invention relates generally to a web loading and feeding system 
including a web and a web handling machine such as a plotter, recorder or 
sign maker. The web is fed longitudinally of itself through the machine by 
a pair of sprockets cooperating with holes in two longitudinal side edge 
portions of the web. The invention deals more particularly with the web 
for the machine and the pair of sprockets within the machine, the web 
having a hole arrangement and the sprockets having a pin arrangement which 
together indicate the proper loading orientation of the web on the 
sprockets. 
Sprockets in machines of the type with which this invention is concerned 
are typically mounted for rotation about a common drive axis and have pins 
or teeth-like members on their peripheries which engage rows of holes in 
two side edge portions of a web being fed. To ensure error free operation, 
it is important that the web is properly loaded on the machine so that the 
sprocket pins engage the correct web holes. This means that two 
corresponding pins of the two sprockets located in a common plane passing 
through the sprocket drive axis engage two corresponding holes in the web 
located on a common line extending perpendicular to the longitudinal side 
edges of the web. When the web is very wide, it is difficult to visually 
determine which sprocket pins correspond with one another and which holes 
on the opposite sides of the web correspond with one another and, as a 
result, web loading errors may occur. The resultant errors in pattern 
cutting or plotting may be small depending on the degree of misalignment, 
so the error may go undetected for a considerable period of time, wasting 
much web material and human labor. 
Patent application Ser. No. 529,960 by Logan filed Sept. 6, 1983 and now 
U.S. Pat. No. 4,834,276, and corresponding South African Patent No. 
84/1909 issued on 9-26-84 disclose a web loading and feeding system which 
provides means to identify the proper loading orientation of a web on a 
pair of drive sprockets. As disclosed there in reference to one embodiment 
of that invention, each of the sprockets has a series of radially, 
outwardly extending driving pins uniformly spaced around the sprocket's 
periphery and an extra keying pin situated between two of the driving 
pins. The keying pins of the two sprockets are located in a common plane 
passing through the axis of the sprockets. An associated web has a 
longitudinal row of uniformly spaced driving holes in each side edge 
portion, the spacing of the driving holes corresponds to the spacing of 
the driving pins. In addition to the driving holes, the web has a 
longitudinal row of keying holes in each side edge portion, the keying 
holes in one side edge portion laterally align with the keying holes in 
the other side edge portion. Also, the spacing of the keying holes in each 
row corresponds to the size of the sprocket and the location of the keying 
pins so that the web may be correctly loaded on the sprockets by placing a 
pair of laterally aligned keying holes over the keying pins of the 
sprockets. 
In the No. 529,960 embodiment described above, the keying pins and the 
driving pins on both sprockets have the same shape, and the keying pin on 
each sprocket is somewhat spaced from the closest driving pin. Also, in 
that embodiment, the keying holes in each side edge portion have the same 
shape as the driving holes and each keying hole is spaced from the nearest 
driving hole by a distance corresponding to that between the keying pin 
and the closest driving pin. 
Such a web loading and feeding system has proven effective in minimizing 
web loading errors of the foregoing type; however, it is desirable to 
further improve the ease at which and the assurance with which the proper 
web loading orientation may be visually determined. 
Accordingly, a general aim of the invention is to provide a web loading and 
feeding system comprising a web having a hole arrangement and sprockets 
having a pin arrangement which web and sprockets readily enable a machine 
operator to visually determine which holes of the web to place over which 
pins on the sprockets to properly load the web. 
A more specific aim of the invention is to provide a web of the foregoing 
type having a hole arrangement which wastes little of the web material. 
Other aims and advantages of the invention will become apparent from the 
following detailed description of the preferred embodiments and from the 
accompanying drawings. 
SUMMARY OF THE INVENTION 
The invention resides in an elongated web for a web handling machine and a 
pair of web drive sprockets within the machine, which web and sprockets 
readily enable an operator to visually determine how to properly load the 
web onto the sprockets and make it virtually impossible for the machine to 
feed an improperly loaded web without the error being obvious. According 
to one feature of the invention, each of the sprockets has a series of 
radially outwardly extending driving pins located in a common plane and 
uniformly spaced from one another around most of its periphery; the 
driving pins of one sprocket laterally align with the driving pins of the 
other sprocket. Each sprocket also includes at least one keying pin having 
a shape and appearance different from that of the driving pins which 
keying pin or pins emanate from the remaining portion of the periphery; 
the keying pin or pins of one sprocket laterally align with the keying pin 
or pins of the other sprocket. 
Also, according to this feature of the invention, the web includes driving 
holes located in each side edge portion, which driving holes are co-linear 
with one another and grouped into sets separated by keying zones. Each 
driving hole on one side of the web is laterally aligned with a driving 
hole on the other side of the web, and each keying zone includes one 
keying hole which, in turn, receives a keying pin of each sprocket. The 
shape of the keying holes is different than the shape of the driving 
holes, particularly insofar as each keying hole has a length much larger 
than each driving hole. Also each keying zone has a length greater than 
two times and less than three times the length of the regular spacing 
between the driving holes. Therefore, the keying zones and keying holes 
are easily identified for placement of the keying holes on corresponding 
keying pins to assure proper web loading.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, the invention is there illustrated as embodied within 
a web loading and feeding system 8 which includes a sign making machine 10 
and an associated web 12. The machine 10 is of the type shown and 
described in more detail in U.S. Pat. No. 4,467,525 to Logan and Sullivan 
issued Aug. 28, 1984, assigned to the assignee of the present invention 
and hereby adopted by reference as part of the present disclosure. The web 
has holes (discussed in more detail below) in its side edge portions and 
is moved longitudinally of itself, in the illustrated X-coordinate 
direction, by a pair of drive sprockets 14,16 which are supported for 
driven rotation in unison about a common drive axis 18 and have pins or 
teeth which engage the holes. A platen or roller 17 located between the 
two sprockets 14 and 16, and similar to that of a typewriter, supports a 
transverse portion of the web 12 aligned with the sprockets 14,16. 
The machine 10 further includes two web holddown bails, one for each 
sprocket 14 and 16, carried by a transverse rod 20 which bails normally 
hold the web in engagement with the sprockets. In FIG. 1 only one such 
holddown bail 22 associated with the sprocket 14 is shown and this bail 
along with the supporting rod 20 is shown in its raised position to give a 
clearer view of the associated sprocket. 
The machine 10 also includes a tool head 24 suitably supported and driven 
in the illustrated Y-coordinate direction relative to the web 12. 
In a normal sign making mode of operation, the tool head 24 is equipped 
with a knife-type cutter 26 and the web 12 is an elongated piece of sign 
making stock. The web 12 and the tool 26 are moved relative to one another 
simultaneously in the X- and Y-coordinate directions through the operation 
of the machine 10 to cut alphanumeric characters or other indicia from the 
sign making stock. Later, the cut characters or indicia are transferred to 
another carrier to form a finished sign. 
The machine 10 also may be operated in a plotting mode during which a 
pencil or other plotting instrument is placed in the head 24 in place of 
the cutting tool 26 and a webbed sheet of paper or the like is fed through 
the machine. One purpose of the plotting mode is to allow a proposed sign 
to be plotted first on paper to check the accuracy of the information 
entered into the machine before the more expensive sign making stock is 
cut. 
Because the machine 10 is typically operated in both the plotting and 
cutting modes and many different sign patterns are plotted and cut during 
the course of a day and there is a wide variety of sign making web 
materials from which the patterns may be cut, an operator must load a web 
onto the machine many times each day. When the web is properly loaded, 
lines extending laterally of the web, that is perpendicular to its side 
edges, are parallel to the sprocket axis 18 as the web is fed 
longitudinally of itself through the machine by rotation of the sprockets. 
Typically, the web 12 may be wide, for example, fifteen inches, and the 
holes formed in each side edge portion of the web may be closely spaced to 
one another, for example, on one-half inch centers or less and if the web 
is loaded onto the sprockets even one hole out of alignment, errors in 
cutting or plotting may occur. 
Referring to FIG. 2, the two sprockets 14 and 16 of the web loading and 
feeding system 8 are both fixed to a common drive shaft 28 for rotation 
about a common axis 18. The sprocket 14 has a series of radially outwardly 
extending driving pins 30, 30 located in a common plane perpendicular to 
the axis 18 and uniformly spaced from one another around a large portion 
of the perimeter of the sprocket 14 as indicated by an arc 31. In a manner 
identical to the spacing of the driving pins 30, 30 of the sprocket 14, 
the sprocket 16 has a series of radially outwardly extending driving pins 
32, 32 located in a common plane perpendicular to the axis 18 and 
uniformly spaced from one another around a large portion of the perimeter 
of the sprocket 16 as indicated by an arc 33. In the illustrated 
embodiments the number of pins 30, 30 on the sprocket 14 and the number of 
pins 32, 32 on the sprocket 16 is twelve; however, this number may vary 
from device to device. Furthermore, the sprockets 14 and 16 are so 
relatively arranged that each pin 30 is at least substantially aligned 
with and corresponds to a pin 32 so that each corresponding pair of pins 
are located in, or at least substantially in, a common plane passing 
through the axis 18. For example, in FIG. 2 one such common plane is shown 
at ABCD and contains a pair of corresponding pins 30 and 32 indicated as a 
and b. 
In keeping with the invention, the sprocket 14 includes two enlarged keying 
pins 34, 34 and the sprocket 16 includes two enlarged keying pins 36,36. 
The keying pins 34,34 are located on a portion of the periphery of the 
sprocket 14 defined by an arc 35 which portion compliments the much larger 
portion defined by the arc 31 and are also located in the same plane 
perpendicular to the sprocket axis 18 as the driving pins 30, 30. Likewise 
the keying pins 36,36 are located on a portion of the periphery of the 
sprocket 16 defined by an arc 37 which portion compliments the much larger 
portion defined by the arc 33 and are also located in the same plane 
perpendicular to the sprocket axis 18 as the driving pins 32,32. Each 
keying pin 34 aligns with and corresponds to a keying pin 36 so that each 
corresponding pair of such keying pins is located in a common plane 
passing through the axis 18, such as a plane at AEFD containing the keying 
pins indicated as d and e. 
The pair of keying pins 34, 34 stands out from the driving pins 30, 30 
because the keying pins of the pair are larger and spaced closer to each 
other than are the driving pins 30, 30, and likewise the pair of keying 
pins 36,3 stands out from the driving pins 32,32 because the keying pins 
36,36 are larger and spaced closer to each other than are the driving pins 
32,32. Consequently, the keying pins 34,34 and 36,36 visually identify 
laterally aligned portions of the sprockets 14 and 16 to aid in loading 
the web correctly. 
The web 12, as shown in FIGS. 2, 4 and 6, comprises an elongated piece of 
sheet-like material having parallel side edges 40 and 42. Sets or row 
segments 43,43 of the driving holes 44,44 are located in a side edge 
portion of the web 12 adjacent the side edge 40. All the holes of all the 
row segments 43,43 are located on a first line 46 spaced slightly inwardly 
from the edge 40 and the holes within each row segment are uniformly 
spaced from one another by a spacing corresponding to the spacing between 
the pins 30, 30 of the sprocket 14. Likewise, sets or row segments 45,45 
of driving holes 48,48 are located in an edge portion adjacent the edge 
42. All the holes of all the row segments 45,45 are located on a line 50 
spaced slightly inwardly from the edge 42 and the holes within each row 
segment are uniformly spaced from one another by a spacing corresponding 
to the spacing between the driving pins 32,32 and equal to that of the 
spacing of the driving holes 44,44. 
Furthermore, as shown in FIG. 4 each driving hole 44 laterally aligns with 
and corresponds to a driving hole 48, for example, the driving holes 
identified as g and h lie on a common line 71 extending perpendicular to 
the web side edges and perpendicular to the lines 46 and 50 containing the 
rows of holes. 
The web 12 also includes enlarged keying holes 54,54 on the line 46 within 
keying zones 47,47 which keying zones and keying holes separate the row 
segments 43,43 from one another. Likewise the web 12 includes enlarged 
keying holes 56,56 on the line 50 within keying zones 49,49 which keying 
zones and keying holes separate the row segments 45,45 from one another. 
All the holes in the web 12 are shown as being round, but this need not 
always be the case. As shown in FIGS. 2, 4 and 6, the keying holes 54,54 
within each keying zone 47 are spaced closer to each other than are two 
adjacent drive holes 44,44 within each row segment 43. By way of example, 
the distance between the center of the driving hole 44 adjacent one side 
of the keying zone 47 and the center of the driving hole 44 adjacent the 
other side of the keying zone 47 is twice the distance between the centers 
of any two adjacent driving holes 44,44 within a row segment. Furthermore, 
in this example the keying holes 54,54 within each keying zone straddle a 
point on the web equidistant between the two adjacent, surrounding driving 
holes 44,44; the distance from each of these driving holes 44 to the 
equidistant point equals the distance between two adjacent drive holes 
within each row segment 43. Similarly the keying holes 56,56 straddle a 
point equidistant between the two adjacent, surrounding drive holes 48,48; 
the distance from each of these driving holes 48 to the equidistant point 
equals the distance between two adjacent driving holes within each row 
segment 45. 
Each keying hole 54 laterally aligns with and corresponds to a keying hole 
56, for example, the keying holes identified as i and j in FIG. 4 lie on a 
common line 58 extending perpendicular to the side edges 40, 42 of the web 
and to the lines 46 and 50. Therefore, as evident from FIGS. 2 and 4, the 
keying holes 54,54 within one keying zone 47 and the corresponding keying 
holes 56,56, by their large size and close spacing, identify aligned 
regions of the side edge portions of the web to be placed over the keying 
pins 34,34 and 36,36 to ensure proper loading of the web 12 on the 
sprockets 14 and 16. 
To load the web 12, the sprockets are turned to move the keying pins 34,34 
and 36,36 upwardly to a web loading position and the web is then moved 
downwardly onto the sprockets bringing the keying holes 54,54 and 56,56 
onto the keying pins 34,34 and 36,36 and bringing the drive holes 44,44 
and 48,48 which surround the keying holes at least partially onto the 
corresponding driving pins 30,30 and 32,32. The engagement of the driving 
holes by the driving pins may be only partial because of the curvature of 
the sprockets 14 and 16. Accordingly, proper movement of the web from that 
point on is assured. 
The holes 44,44 and 54,54 longitudinally align with one another as near the 
side edge 40 as practical to maximize the usable area of the web 12 but to 
avoid tearing when subjected to forces of engaging pins. For the same 
reasons and with the same constraints, the holes 48,48 and 56,56 
longitudinally align with one another as near the side edge 42 as 
practical. Also, the longitudinal alignment of the holes 44,44 with the 
holes 54,54 and that of the holes 48,48 with the holes 56,56 allow the use 
of relatively simple sprockets 14 and 16. If the holes in one side edge 
portion of the web were not all longitudinally aligned with one another, 
then a second sprocket or a lateral extension of the respective sprocket 
14 or 16 may be required to mount pins capable of reaching and engaging 
all the holes. 
In the illustrated embodiment, pairs of keying holes 54,54 and pairs of 
keying holes 56,56 are spaced uniformly from one another along the length 
of the web by a distance S equal to (N+1)d, where d is the spacing between 
two driving holes 44,44 within a row segment and is the spacing between 
two adjacent driving holes 48,48 within a row segment, and where N is the 
number of driving pins 30,30 on the sprocket 14 and the number of driving 
pins 32,32 on the sprocket 16. In the illustrated case the number of pins 
30,30 is twelve as is the number of pins 32,32 and therefore S equals 13d. 
Each time the sprockets 14 and 16 undergo one revolution the keying pins 
34,34 engage two keying holes 54,54 and the keying pins 36,36 engage two 
corresponding keying holes 56,56, and the 12 driving pins 30,30 engage the 
12 driving holes 44,44 within one row segment 43 and the 12 driving pins 
32,32 engage the 12 driving holes 48,48 within one row segment 45. 
As indicated previously, the web 12 may take various different forms and, 
in FIG. 5, the web 12 is shown to comprise a piece of sign making stock 
having an upper layer 60 and a release layer 64. The upper layer is made 
of a thermoplastic material such as vinyl on the order of three to five 
mils thick with an adhesive backing or coating 62. This upper layer is 
supported on the release layer 64 and releasably held by the adhesive 
backing 62. The release layer may consist of a ninety-pound paper coated 
or impregnated with silicone to give it its release property. 
If a type of web utilized with the machine 10 exhibits significant 
variations in width due to variations in temperature and humidity or 
manufacture tolerance, then a spline shaft and a sprocket slidably mounted 
thereon may be substituted for the sprocket 14 and the shaft 28 to 
accommodate such variations. 
FIG. 7 illustrates another web 97 embodying the invention, which web is 
adapted to fit over the sprockets 14 and 16 despite the fact that the 
sprockets are fixed to the shaft and the width of the web 97 may differ 
from that of the web 12 due to variations in temperature and humidity or 
manufacture tolerance. The web 97 is identical to the web 12 except that 
the web 97 includes row segments 91,91 of laterally elongated driving 
holes 90,90 instead of row segments 45,45 of the round driving holes 
48,48, and laterally elongated keying holes 92,92 instead of the round 
keying holes 56,56, the lateral elongation of the driving and keying holes 
compensates for the variation in web width by accommodating the driving 
and keying pins of the sprocket 16 despite such variations. 
The keying holes 92,92 are located in keying zones 95,95 between the row 
segments, and the driving holes 90,90 and the keying holes 92,92 are 
located along a line 93 parallel to the side edges of the web 97. Each 
driving hole 90 laterally aligns with and corresponds to a driving hole 44 
as indicated by a line 101 which is perpendicular to the side edges of the 
web and the line 93 and passes through the driving hole 44 indicated as k 
and the driving hole 90 indicated as 1. Each keying hole 92 laterally 
aligns with and corresponds to one of the keying holes 54 as indicated by 
a line 99 which is perpendicular to the side edges of the web 97 and 
passes through the keying hole 54 indicated as m and the keying hole 92 
indicated as n. The keying holes 92,92 are wide enough in the longitudinal 
direction to fit over the keying pins 36,36, and the driving holes 90,90 
are wide enough in the longitudinal direction to fit over the driving pins 
32,32 but not over the keying pins 92,92. Also, the keying holes 92,92 are 
somewhat longer in the transverse direction than the driving holes 90,90 
because the keying pins are broader than the driving pins. Also, because 
the keying holes 92,92 of each keying zone are longer, wider, and spaced 
closer to each other than are the driving holes 90,90, the keying holes 
stand out, and because the keying holes 92,92 within each keying zone 93 
laterally align with the corresponding keying holes 54,54, the keying 
holes 92,92 and 54,54 together with the keying pins 34,34 and 36,36 
identify the proper loading orientation of the web 97. 
FIGS. 8-10 illustrate another preferred embodiment of the invention, and 
more specifically, FIG. 8 shows two sprockets 114 and 116 fixed to a 
common drive shaft 128 for rotation about a common axis 118. The sprocket 
114 has a series of radially outwardly extending driving pins 130,130 
located in a common plane perpendicular to the axis 118 and uniformly 
spaced from one another entirely around the periphery of the sprocket. The 
sprocket 116 has a similar series of radially outwardly extending driving 
pins 132,132 located in a common plane perpendicular to the axis 118 and, 
in a manner identical to the spacing of the pins 130,130 on the sprocket 
114, the driving pins 132,132 are uniformly spaced from one another 
entirely around the periphery of the sprocket 116. The number of pins 
130,130 and 132,132 may vary from application to application, but in the 
illustrated case the sprocket 114 has thirteen pins 130,130 and the 
sprocket 116 likewise has thirteen pins 132,132. Furthermore, the 
sprockets 114 and 116 are so relatively arranged that each driving pin 130 
on the sprocket 114 aligns with and corresponds to a driving pin 132 on 
the sprocket 16, each pair of which corresponding driving pins are located 
in a common plane passing through the axis 18. For example, in FIG. 8 one 
such common plane LMNO contains a pair of corresponding driving pins 130 
and 132 indicated as a and b, respectively and another such common plane 
LPQO contains a pair of corresponding driving pins 130 and 132 indicated 
as e and f. 
The sprocket 114 includes two extra keying pins 134,134 which closely 
surround the driving pin 130 indicated as e and the sprocket 116 includes 
two extra keying pins 136,136 which closely surround the driving pin 132 
indicated as f. 
Each keying pin 134 aligns with and corresponds to a keying pin 136 as 
illustrated by a plane LSTD containing the axis 118 and intersecting two 
such corresponding keying pins 134 and 136 indicated as g and h, 
respectively. 
The keying pins 134,134 and the associated driving pin 130 form a cluster 
of pins or keying projection 131 which stands out from the other pins on 
the sprocket 114 and, similarly, the keying pins 136,136 and associated 
driving pin form a cluster of pins or keying projection 133 which stands 
out from the other pins on the sprocket 116. If desired, each keying 
projection 131 and 133 may also be made as a unitary member rather than 
being comprised of three separate pins. The two keying projections 131 and 
133 identify aligned portions of the sprockets 114 and 116. The keying 
projections also serve to drive the web when such projections engage 
keying openings in the web. 
The web 112, as shown in FIGS. 8, 10 and 11 comprises an elongated piece of 
sheet-like material made from any material from which the web 12 may be 
made and has parallel side edges 140 and 142. A row of driving holes 
144,144 is located in a side edge portion of the web 112 adjacent the side 
edge 140 on a line 146 spaced slightly inwardly from the edge 140, which 
holes are uniformly spaced from one another by a spacing corresponding to 
the spacing between the pins 130,130 of the sprocket 114. Likewise, a row 
of driving holes 148,148 is located in a side portion adjacent the edge 
142 on a line 150 spaced slightly inwardly from the edge 142 which holes 
are uniformly spaced from one another by a spacing equal to that of the 
spacing of the holes 144,144. Each driving hole 144 laterally aligns with 
and corresponds to a driving hole 148 as indicated by lines 152 and 153 
shown in FIG. 10 which lines extend perpendicular to the side edges 140 
and 142. 
The web 112 also includes keying holes 154,154 located on the same line 146 
as the driving holes 144,144 and keying holes 156,156 located on the same 
line 150 as the driving holes 148,148. The keying holes 154,154 laterally 
align with corresponding keying holes 156,156 as indicated by lines 155 
and 157 shown in FIG. 10 which extend perpendicular to the side edges 140 
and 142 of the web 112. All the holes in the web 112 are shown as being 
round, but this need not always be the case. The keying holes 154,154 are 
situated in pairs at intervals along the length of the web, each pair 
closely surrounding and adjoining an associated driving hole 144 forming a 
cluster of three holes. Local webbings 161,161 (indicated in FIG. 11 by 
broken lines) between the keying holes and the associated driving hole are 
omitted from webs made of paper, sign making stock, and other web 
materials because such local webbing was found to be too flimsy to 
contribute much in the way of drive engagement with the driving and keying 
pins and often broke from the web and littered the machine 10. Also, the 
removal facilitates the visual identification of the clusters for loading 
purposes. Thus a pair of keying holes 154,154 and an associated drive hole 
144 form an interconnected cluster of holes which together provide a 
single keying opening 163 which is elongated in the longitudinal direction 
of the web 112 so as to have a shape and length different from the driving 
holes 144 and so as to therefore stand out from the other holes because of 
its shape and large size. Likewise, the keying holes 156,156 are situated 
in pairs at intervals along the length of the web, each pair closely 
surrounding an associated driving hole 148, so close that local webbings 
analogous to the local webbings 161,161 are omitted for the reasons stated 
above. Thus, a pair of keying holes 156,156 and an associated driving hole 
148 form an interconnected cluster of holes identical to that shown in 
FIG. 11, which cluster provides a single keying opening 165 standing out 
from the other holes. The illustrated keying openings 163 and 165 
therefore each have a shape corresponding to three closely spaced circular 
holes with their centers on a line extending longitudinally of the web 112 
and spaced from one another by the diameter of each hole. Such shape 
however is not essential to the broader aspects of the invention and other 
shapes elongated longitudinally of the web may be employed with the keying 
projections of the sprockets being complementarily shaped. 
The holes 144,144 and 154,154 longitudinally align with one another as near 
the side edge 140 as practical to maximize the usable area of the web but 
to avoid tearing when subjected to forces from engaging pins. Similarly, 
the holes 148,148 and 156,156 longitudinally align with one another as 
near the side edge 142 as practical. Also, the longitudinal alignment of 
the holes 144,144 and 154,154 and that of the holes 148,148 and 156,156 
allow the use of relatively simple sprockets; if any of such holes were 
out of alignment with the others, then a second sprocket or a lateral 
extension of the sprockets 114 and 116 may be required to provide pins 
which are able to reach all of the holes. 
To load the web 112 onto the sprockets 114 and 116, the sprockets are 
turned to move the keying projections 131 and 133 upwardly to a web 
loading position. Then, the web 112 is moved over the sprockets until a 
corresponding pair of keying openings 163 and 165 as shown in FIG. 8 are 
located above the keying projections and the web is moved downwardly onto 
the sprockets bringing the keying openings onto the keying projections. 
Thereafter, proper movement of the web is assured. 
With reference to FIG. 10, the keying openings 163 are spaced uniformly 
from one another along the length of the web at intervals S equal to Nd, 
where d is the spacing or interval between adjacent driving holes 144,144 
is the spacing between adjacent driving holes 148,148, and where N is the 
number of driving pins 130,130 on the sprocket 114 and is the number of 
driving pins 132,132 on the sprocket 116. In the illustrated case, the 
number of pins 130,130 and 132,132 is thirteen and therefore, its keying 
openings 163 occur periodically along the length of the web at intervals 
S=13d and likewise the keying openings 165 occur periodically along the 
length of the web at intervals S=13d. Furthermore, each time the sprockets 
114 and 116 undergo one revolution the keying projections 131,133 enter 
one pair of keying openings 163,165. If the width of the web 112 may vary 
due to variations in temperature and humidity or manufacture tolerance, 
then one of the sprockets 114 or 116 may be slidably mounted on the shaft 
128 or on a spline shaft. 
Even though each keying opening 163 or 165 has been described as including 
two keying holes and one adjoining driving hole, each keying opening may 
alternatively be viewed as one enlarged, irregularly shaped hole or 
opening situated within a keying zone, which keying zone and associated 
keying opening separate two adjacent row segments of driving holes. 
FIG. 12 illustrates another web 200 embodying the invention which web is 
similar to the web 112 except that the web 200 includes laterally 
elongated drive holes 202,202, instead of the round drive holes 148,148 
and laterally elongated keying holes 210,210, instead of the round keying 
holes 156,156. 
The purpose of providing laterally elongated holes 210,210 and 202,202 in 
one side edge portion of the web is the same as providing the laterally 
elongated holes in the web 97, to allow the web 200 to readily fit over 
the pins of both sprockets 114 and 116 despite the fact that the sprockets 
114 and 116 are fixed to the shaft 128 and the width of the web 200 
differs from that of the web 112 and varies slightly from web to web for 
the reasons discussed above. 
The keying holes 210,210 and the driving holes 202,202 are located along a 
line 206 parallel to the sides of the web 200 and inwardly spaced from one 
side edge 208. As indicated by lines 212, 214 and 216 which are 
perpendicular to the side of the web, the holes 202,202 and 210,210 
laterally align with and correspond to the holes 144,144 and 154,154, 
respectively. 
FIGS. 13 and 14 show parts of an exemplary web loading and feeding system 
comprising another embodiment of the invention. FIG. 13 shows the web 220 
of the system, and FIG. 14 shows one sprocket 222, two of which are used 
in place of the sprockets 14 and 16 of the machine 10 of FIG. 1 to feed 
the web 220. 
The web 220 is generally similar to the web 112 of FIGS. 8 to 11 except 
that along each side edge of the web each keying zone has a length which 
is not an integral multiple of the regular spacing between the driving 
holes, and except for there being a different number of driving holes 
between successive keying zones. The non-integral length of the keying 
zones in combination with the fact that the keying opening in each keying 
zone has a length and shape different from each driving hole therefore 
makes the keying zones and keying openings still more visibly discernable 
from the driving holes. 
In particular, the illustrated web 220 along one side edge has a plurality 
of driving holes 144 and keying openings 163 arranged along a straight 
line 146 extending longitudinally of the web. In the other side edge 
portion of the web are a plurality of driving holes 148 and keying 
openings 165 arranged along another straight line 150 extending 
longitudinally of the web. 
As shown for the holes and openings on the line 150 of FIG. 13, the driving 
holes 148 are located in row segments 224 spaced from one another by 
keying zones 226. The driving holes 48 are all of uniform circular size 
and shape and are spaced from one another by a regular interval or spacing 
d. Each row segment 224 has a length of 9d so as to start at the center of 
a first driving hole 148 and to stop at the center of a tenth driving hole 
148. Each keying zone 126, as mentioned, has a length greater than two 
times and less than three times the regular spacing d of the driving 
holes. The exact length of the keying zone may vary, but in the 
illustrated case such length is shown to be 2.37 d. 
Each keying opening 165 of the web 220 of FIG. 13 has a shape similar to 
the keying opening 163 shown in FIG. 11. That is, each keying opening 165 
has a shape corresponding to three driving openings 148 arranged close to 
one another along the line 50 and communicating with one another so as to 
form a single elongated opening. Preferably, and as shown in FIG. 11, the 
three holes making up each keying opening are arranged with their centers 
spaced from one another by a distance substantially equal to the diameter 
of each hole, and small portions of the web, such as indicated at 161 in 
FIG. 11 by the broken lines, are also omitted, giving the keying opening a 
more unitary appearance. 
The driving holes 144 and keying openings 163 arranged along the other edge 
of the web 220 are arranged similarly to the driving holes 148 and keying 
openings 165, with one driving hole 144 being located transversely 
opposite a driving hole 148 and with each keying opening 163 being located 
transversely opposite a keying opening 165. Therefore, each pair of keying 
openings 163 and 165 constitutes a pair visibly distinguishable from the 
driving holes aiding in the proper location of the web 220 on the 
associated sprockets of the machine 10. 
A sprocket 222 for use with the web 220 of FIG. 13 is illustrated in FIG. 
14. As there illustrated, the sprocket has ten driving pins 228 located 
along a first circumferential portion of the sprocket and regularly spaced 
from one another by a spacing of 31.65.degree.. The sprocket also includes 
a keying projection 230 comprised of three closely spaced pins 232,232. 
The center one of these pins 232 is located midway between the adjacent 
two of the driving pins 228. That is, the middle pin 232 is located 
37.57.degree. from the driving pin 228 located on one side of it and is 
located 37.57.degree. from the driving pin 228 located on the other side 
of it. 
In use with the web 220 of FIG. 13 two sprockets 222 such as shown in FIG. 
14 replace the sprockets 14 and 16 of the machine 10 as shown in FIG. 1. 
During loading of the web onto the machine a pair of keying openings 163 
and 165 is fitted over the two keying projections 230 on the two 
sprockets. Thereafter, as the sprockets rotate the driving pins 228 of the 
sprockets enter and cooperate with the driving openings 144 and 148 of the 
web and the keying projections 230 enter and cooperate with the driving 
openings 163 and 165 to feed the web longitudinally of itself. 
By the foregoing, web loading and feeding systems have been disclosed 
embodying the present invention. However, numerous modifications and 
substitutions may be made without deviating from the spirit of the 
invention. For example, the keying projections and the driving pins on any 
sprocket may be made a different color to further visually identify 
corresponding, aligned portions of the sprockets. In addition, the driving 
holes and keying openings may be made square and/or rectangular if 
desired. Also, the local webbings 161,161 of the web 112 need not be 
removed if desired. 
It is also possible to provide a web loading and feeding system similar to 
that of the system 8 in which the pins on one sprocket are angularly 
advanced relative to the corresponding pins on the other sprocket, and the 
holes in the corresponding side edge portion of the web are similarly, 
longitudinally advanced relative to the holes in the other side edge 
portion. 
Therefore, the invention has been described by way of illustration and not 
by limitation.