A conveyor belt of stretchable elastomeric material reinforced by layers of cords which permit an initial stretching of the belt at installation of at least 3 percent. Reinforcing cords are positioned in the belt elastomeric material to generate transverse forces during stretching of the belt which results in the interaction of the material of the belt with the cords. This interaction causes the edge portions of the belt to curl upwardly and form load-retaining walls at the edges. The belt may have a bottom stretchable portion which is reinforced to resist outside transverse forces resulting from the passage of the belt around a curve. A top stretchable portion of the belt has edge portions which bend upwardly to form the load-retaining walls. The edge portions of the belt may curl sufficiently to bring the edges together and they may be connected for enclosing the load on the belt surface.

In most belt conveyors the belt is manufactured in a flat configuration but 
is troughed for retaining the conveyed material by rollers set at an angle 
and engaging the edge portions. Belts have also been molded in a U-shape 
such as the belt of my U.S. Pat. No. 4,061,223. In another case it was 
proposed to transversely prestretch the upper ply of a belt prior to 
curing so that after curing it would contract and cause the belt edges to 
curve upwardly. It has also been proposed to make the plies at the edges 
of the belt of materials having different coefficients of expansion so 
that during operation in a low temperature environment the edge portions 
will be curled upward and retain a fluid material. Other belts have been 
proposed having hinged edge portions which are supported by special 
brackets between a supporting power belt and the load-carrying container 
belt. 
In some cases it is desirable to enclose the space over the load-carrying 
surface and belts have been made with retaining walls which have 
connecting edges. These belts have usually required elaborate mechanical 
equipment for connecting and disconnecting the edges. 
The present invention is directed to a conveyor belt which is stretchable a 
predetermined amount upon installation. The belt edge portions curl up 
during the stretching and provide load-retaining walls. These walls may 
curl a greater or lesser amount depending on the belt construction and, 
where desired, may curl enough to connect the edges and enclose the 
material being conveyed. The belt edge portions curl up upon longitudinal 
stretching of the belt due to the interaction of belt narrowing means 
responsive to stretching of the belt and means resisting narrowing of the 
belt. The belt narrowing means are closer to the load-carrying surface 
than the resisting means whereby tension on the belt generates transverse 
force bending the edge portions of the belt to form retaining walls for 
the load carried by the belt. 
The belt narrowing means can be one or more layers of bias cords which 
pantograph upon elongation of the belt. 
The means resisting narrowing can be a layer of transversely extending 
cords or the elastomeric material of the belt. 
It is usually desirable to have a belt cover at the load-carrying surface 
to protect the belt narrowing cords but the means resisting narrowing 
under the narrowing means must be sufficient to overcome the resistance of 
the elastomeric material of the cover and provide a sufficient net 
resistance in the desired direction to produce the curvature needed. 
Since the edges of the belt in the present invention are under sufficient 
tension to hold the load without distortion, simple flat rollers may be 
used to support the load-carrying belt run. 
Another advantage is derived from the minimum tension required to stretch 
the belt a predetermined amount upon installation. This minimum tension is 
more or less maintained throughout the belt length providing a built-in 
take-up action distributed along the entire belt conveyor rather than 
concentrating this action at a single point on the conveyor which may be a 
considerable distance from where the take-up action is needed. 
The novel construction thus provides a more uniform distribution of 
stresses and makes possible a conveyor which may have rollers spaced apart 
a greater distance than rollers for a conventional conveyor.

Referring to FIGS. 1 and 2, a conveyor 10 is shown located in a horizontal 
position for conveying bulk materials such as coal from a loading belt 11 
at one end to an unloading belt 12 at the other end. The conveyor 10 has a 
stretchable conveyor belt 13 extending over terminal pulleys such as tail 
pulley 14 and discharge pulley 15 located at the ends of the conveyor. A 
suitable belt drive 16 includes an electric motor 17 or other suitable 
power means connected to the discharge pulley 15 by a flexible chain or 
belt drive assembly 18. 
With reference to FIGS. 1 and 3, a load-carrying upper run 19 of the 
conveyor belt 13 is supported by support rollers 22 mounted on roller 
frames 23 spaced longitudinally along the conveyor 10. A lower run 24 of 
the conveyor belt 13 is supported on split rollers 25 rotatably mounted on 
center supports 26 which are fastened to the roller frames 23. 
As shown in FIGS. 4 and 6, the conveyor belt 13 includes an elongated 
elastomeric body of rubber or other rubberlike material with spaced-apart 
edges 27 and 28. A load-carrying belt surface 31 extends between the edges 
27 and 28 and is located at the top side of the belt when in the 
load-carrying upper run 19 of the conveyor 10. 
The conveyor belt 13 is stretchable at least 3 percent when subjected to 
longitudinal forces in tension and is mounted in tension on the conveyor 
10. In this embodiment the conveyor belt 13 is spliced at a length such 
that the belt is elongated at least 3 percent when in the mounted position 
on the conveyor 10. 
Belt narrowing means responsive to stretching of the belt 13 such as first 
and second layers 32 and 33 of bias cord reinforcing material generate 
predetermined transverse forces in a direction to reduce the width of the 
belt upon stretching during the initial installation on the conveyor 10. 
Since the transverse forces generated by the layers 32 and 33 are closest 
to the upper belt surface 31 and are resisted by the stiffness of the 
underlying material, the edges 27 and 28 and edge portions 29 and 30 of 
the belt 13 are caused to curl or bend upwardly, as shown in FIG. 5, and 
thereby provide retaining walls 34 and 35 at the edges for retaining 
material on the belt surface. 
In other words, the first and second layers 32 and 33 are positioned closer 
to the belt surface 31 carrying the load than they are to the surface on 
the other side of the belt and this is believed to contribute further to 
bending of the edge portions 29 and 30 upwardly along the belt surface 31. 
Also, as shown in FIG. 4, the first and second layers 32 and 33 separate 
the resilient material of the conveyor body into an upper portion 36 
between said layers and the belt surface 31 and a lower portion 37 on the 
other side of the first and second layers. Accordingly when the belt 13 is 
stretched the reduction in width of the belt surface 31 between the edges 
27 and 28 is greater than the reduction in width of the belt at the lower 
portion 37 which further contributes to the curling or bending of the 
edges upwardly and away from the belt surface 31. 
The belt 13, shown in detail in FIGS. 4, 5 and 6, has a top cover 38 which 
may be of the same resilient material as the rest of the belt, or may be 
of a more wear-resistant material, because the belt surface 31 over this 
cover is exposed to abrasion from the material to be conveyed. The elastic 
material of the belt 13 is highly stretchable and has a hardness on the 
durometer scale from about 60 to 80. For installations in coal mines the 
material may be a flame-resistant elastomer. For above-ground operation, 
the material of the belt 13 may be any conventional wear-resistant rubber 
such as those known as GRS and SBR rubbers. The first and second layers 32 
and 33 have reinforcing cords 39 and 40 laid on a bias of about 55 degrees 
and may be at angles in the range of from about 40 degrees to about 60 
degrees relative to a transverse axis A--A of the belt shown in FIG. 6. 
The first layer 32 extends from edge 27 to edge 28 and the second layer 33 
is coextensive with and positioned under the first layer, but with the 
cords 40 laid at an opposite bias angle to the cords 39 of the first 
layer. 
A third layer 43 of reinforcing cords is coextensive with and positioned 
under the second layer 33 and is formed of parallel cords 44 extending 
substantially transversely of the belt 13. A fourth layer 45 of 
reinforcing cords 46 is positioned under the third layer 43 with layer 
edges 47 and 48 spaced from the edges 27 and 28 of the belt 13. The cords 
46 of the fourth layer 45 are laid on a bias at substantially the same 
angle as the cords 39 of the first layer 32. A fifth layer 49 of 
reinforcing cords 50 is coextensive with and positioned under the fourth 
layer 45 and has the cords laid on a bias at substantially the same angle 
as the cords 40 of the second layer 33. 
The presence of the narrow band consisting of layers 45 and 49 of 
reinforcing material on the other side of the midplane balances the forces 
so that the reduction in width when the belt is stretched does not curl 
the center of the belt. 
In the belt 13 of this embodiment, the cords 39, 40, 44, 46 and 50 of the 
first through fifth layers 32, 33, 43, 45 and 49 are of polyester and are 
spaced at about 22 ends per inch with each layer having a total thickness 
of about 0.05 inches. Separating or cushioning components 51 of 
elastomeric material are provided between the layers 32, 33, 43, 45 and 49 
so that there can be relative angular movement of the cords 39 and 40, 40 
and 44, 44 and 46, and 46 and 50. The relative movement of the cords 
contributes to the stretching of the belt 13 in the longitudinal direction 
and can be increased or decreased by changing the thickness of the 
cushioning components 51. In building the belt 13, the cords 39, 40, 44, 
46 and 50 may be covered by a skim coat of elastomeric rubber and after 
vulcanization the skim coats of overlapping layers form the cushioning 
components 51. 
In the belt 13, shown in FIGS. 4, 5 and 6, the cords 39, 40, 44, 46 and 50 
have a thickness of about 0.03 inches and a skim coat of from about 0.01 
to 0.02 inches is calendered or otherwise applied to each side of the 
cords resulting in each of the cushioning components 51 having a thickness 
of from about 0.02 to 0.04 inches. When the belt 13 is vulcanized the 
thickness of the cushioning components 51 will be reduced because of the 
removal of air and compacting of the elastomeric material. The top cover 
38 has a thickness of about 0.06 inches and a bottom layer or bottom cover 
53 of the belt 13 has a thickness of about 0.06 inches at the center 
portion. The total thickness of the belt 13 in the vulcanized condition is 
about 0.37 inches. The belt 13 of this embodiment has a total width of 
about 38 inches. The width of the fourth and fifth layers is about 20 
inches and the width of each of the edge portions 29 and 30 of the belt is 
about 9 inches. The thickness of the bottom cover 53 is greater by 0.1 
inches or 0.16 inches at the edge portions 29 and 30. This compares with 
the thickness of the top cover 38 of only 0.06 inches. It is therefore 
believed that the greater thickness of the bottom cover 53 adjacent the 
edges 27 and 28 of the belt 13 as compared with the thickness of the top 
cover 38 contributes to the curling or bending of the edge portions 29 and 
30 away from the bottom cover and towards the top cover. In fact it has 
been found that the greater the difference in thickness between the top 
cover 38 and the bottom cover 53 the greater is the tendency of the edge 
portions 29 and 30 to curl. 
The belt 13 is built and vulcanized in a flat condition, as shown in FIGS. 
4 and 6, and then installed in a stretched condition as shown in FIGS. 1, 
2, 3 and 5. The initial stretching of the belt 13 of at least 3 percent 
and preferably in the range of from 3 to 15 percent causes the cords 39 
and 40 of the first and second layers 32 and 33 and the cords 46 and 50 of 
the fourth and fifth layers 45 and 49 to pantograph and progressively 
resist further elongation as the belt is stretched. It has been found that 
with the cord angles of around 55 degrees relative to the transverse axis 
A--A the belt 13 may be stretched between 3 and 15 percent after which the 
resistance to stretching is substantial and sufficient for load-carrying 
operation of the conveyor 10. It has also been found that the 
pantographing of the cords 39 and 40 in the first and second layers 32 and 
33 generates a substantial transverse force which interacts with the 
resistance of the resilient material of the belt 13 and bends the edge 
portions 29 and 30 upwardly to function as retaining walls 34 and 35 as 
shown in FIG. 5. The cords 46 and 50 of the fourth and fifth layers 45 and 
49 neutralize the action of the cords 39 and 40 of the first and second 
layers 32 and 33 at the center portion of the belt 13, thus maintaining a 
relatively flat surface 31 between the curled side edge portions 29 and 
30. The transverse cords 44 of the third layer 43 further resist a 
reduction in width or narrowing of the belt 13 and accordingly contribute 
to the curling or bending of the edge portions 29 and 30. Nevertheless, 
when the belt 13 passes over the tail pulley 14 and discharge pulley 15 it 
will flatten out as shown in FIGS. 1 and 2. 
In the return lower run 24 the belt 13 is in the stretched condition and 
retaining walls 34 and 35 extend downwardly at each side of the split 
rollers 25. As shown in FIG. 3, if the belt 13 in the lower run 24 travels 
to either side, it will be prevented from running off the split rollers 25 
by engagement of the retaining walls 34 and 35 with the ends of the split 
rollers. 
As described hereinabove, when the belt 13 is subjected to a sufficient 
tension, the walls 34 and 35 will be retained in the operating condition 
for containing the bulk material so that the rollers 22 may be 
cylindrical. The substantial tension maintained throughout the length of 
the belt 13 also makes possible a greater spacing between the support 
rollers 22 than is possible with a conventional conveyor belt. 
Referring to FIGS. 7 and 8, a modified construction of a conveyor belt 54 
is shown having an elongated elastomeric body of resilient material with 
spaced edges 55 and 56. A first layer 57 has reinforcing cords 58 laid on 
a bias of about 45 degrees to transverse axis B--B of the belt and extends 
between the edges 55 and 56 of the belt 54. The belt 54 has a 
load-carrying belt surface 59 on a top cover 62 under which the first 
layer 57 is located. A second layer 63 of reinforcing cords 64 is 
positioned under said first layer 57 with the cords laid at an opposite 
bias angle of 45 degrees to the angle of the cords 58 of the first layer. 
The second layer 63 has edges 65 and 66 which are spaced from the edges 55 
and 56 of the belt 54 providing a center portion between the edges 65 and 
66. Edge portions 67 and 68 are also provided between the edges 55 and 65 
and the edges 56 and 66. 
A bottom cover 69 is positioned under the second layer 63 and has a 
thickness of about 0.07 inches at the center portion. The top cover 62 
also has a thickness of about 0.07 inches and the first layer 57 and 
second layer 63 each have a thickness of about 0.05 inches. A cushioning 
component 70 is located between the cords 58 and 64 of the first and 
second layers 57 and 63 and may have a thickness of about 0.01 to 0.02 
inches prior to vulcanization of the belt 54. As shown in FIGS. 7 and 8, 
the thickness of the bottom cover 69 at the edge portions 67 and 68 is 
greater than the thickness at the center portion which further contributes 
to the curling or bending upwards of the edge portions. 
The cords 58 and 64 of the first and second layers 57 and 63 are of a 
suitable textile material such as polyester and may be spaced at about 22 
ends per inch. The width of the belt is about 34 inches with the center 
portion having a width of 10 inches and the edge portions 67 and 68 each 
having a width of about 12 inches in the unstretched condition. The belt 
54 is stretchable at least 3 percent and when stretched decreases in width 
a proportional amount. Also the edge portions 67 and 68 bend upwardly to 
provide retaining walls at the sides of the belt surface 59 in the 
stretched condition in a similar manner to that described hereinabove for 
the embodiment of FIGS. 4, 5 and 6. The cords 64 of the second layer 63 
neutralize the curling action of the cords 58 of the first layer 57 and 
provide a relatively flat surface 59 between the curled side edges 55 and 
56. 
Another modification is shown in FIGS. 9 and 10 in which a belt 71 has an 
elongated elastomeric body with edges 72 and 73 and a belt surface 74 
extending between the edges. The belt 71 has a center portion 75 with 
margins 76 and 77 spaced from the edges 72 and 73 providing edge portions 
78 and 79. The belt surface 74 is on a top cover 82 which has a thickness 
of about 0.07 inches. The top cover 82 may be of a resilient material 
having good wear characteristics as indicated above. Under the top cover 
82 is a first layer 83 of reinforcing cords 84 and 85 in the edge portions 
78 and 79, respectively. The first layer 83 extends from the edges 72 and 
73 of the belt 71 to the margins 76 and 77 of the central portion 75 in 
the edge portions 78 and 79. The cords 84 in the edge portion 78 are laid 
on a bias to the transverse axis C--C at an angle of 45 degrees in one 
direction. The cords 85 of the edge portion 79 are laid at an angle of 45 
degrees to the transverse axis C--C and at an opposite bias angle to the 
cords 84 of the other edge portion 78. Under the first layer 83 is a 
second layer 86 of reinforcing cords 87 and 88 in edge portions 78 and 79 
laid at an angle of 45 degrees to the transverse axis C--C but at an 
opposite bias angle direction to the cords 84 and 85 of the first layer. 
Under the second layer 86 is a third layer 89 of square woven stretch 
fabric 90. This type of reinforcement for a conveyor belt is described in 
my patent application Ser. No. 399,767 which is a continuation-in-part of 
application Ser. No. 181,402, now abandoned, filed concurrently with 
application Ser. No. 181,404 for which this application is a 
continuation-in-part now abandoned. The third layer 89 extends from one 
edge 72 of the belt 71 to the other edge 73. The stretch fabric 90 of the 
third layer 89 has the property of stretching a predetermined distance 
when subject to tension during the initial stretching of the belt 71 and 
then its resistance to further elongation increases rapidly to resist any 
appreciable stretching of the belt in operation. 
In this modification, the top cover 82 has thickness of about 0.07 inches. 
The first layer 83 is of polyester cords spaced at about 22 ends per inch 
with the first layer having a thickness of about 0.05 inches. The second 
layer 86 also has a thickness of about 0.05 inches and polyester cords 
spaced at about 22 ends per inch. A bottom cover 93 under the third layer 
89 has a thickness of about 0.07 inches. Cushioning components 92 are 
located between the cords 84 and 85 of the first and second layers 83 and 
86 and between the cords 87 of the second layer 86 and the stretch fabric 
90 of the third layer 89. The cushioning components 92 may have a 
thickness of about 0.01 to 0.02 inches prior to vulcanization. 
In operation the belt 71 is built and vulcanized in the flat condition as 
shown in FIGS. 9 and 10 with the stretch fabric 90 of the third layer 89 
in the unstretched condition. Upon installation of the belt 71 on a 
conveyor, the belt is initially stretched a predetermined amount of at 
least 3 percent, at which point further stretching of the belt is strongly 
resisted. During the stretching process, the cords 84, 85, 87 and 88 of 
the first and second layers 83 and 86 pantograph and bend the edge 
portions 78 and 79 upwardly at the sides of the belt surface 74 providing 
retaining walls such as those shown in FIGS. 3 and 5. With the stretch 
fabric 90 of the third layer 89 the longitudinal force necessary for 
initial stretching of the belt 71 is less than it would be if the 
stretching of the belt was limited by layers of reinforcing cord laid on a 
bias such as that shown in the modifications of FIGS. 4 through 8. Also 
transverse cords of the stretch fabric 90 resist reduction in width of the 
belt 71 and contribute to the bending of the edge portions 78 and 79. 
Referring to FIG. 11, a belt 71' is shown which is identical to the belt of 
FIGS. 9 and 10 except that in the second layer 86' a center portion 94 has 
been added to fill the space between the margins 76' and 77'. The center 
portion 94 of the second layer 86' is of square woven stretch fabric 95 
having the property of being stretchable upon initial stretching of the 
belt 71' during installation on the conveyor and then having a high 
resistance to further stretching of the belt in operation. The stretch 
fabric 95 of the center portion 94 of the second layer 86' may have the 
same characteristics as the stretch fabric 90 of the third layer 89 of the 
belt 71 shown in FIGS. 9 and 10. The cushioning component 92' between the 
cords of the second layer 86' and the stretch fabric of the third layer 
89' also extends between the stretch fabric of the second and third 
layers. In operation, the belt of FIG. 11 is stretchable and will provide 
upstanding retaining walls in a similar manner to the belt of FIGS. 9 and 
10; however, the belt of FIG. 11 may have greater strength in the 
longitudinal direction in the stretched condition. 
A belt 96 adaptable for movement around curves is shown in FIGS. 12, 13 and 
14. The belt 96 has an elongated elastomeric body with a top portion 97 
and a bottom portion 98 connected at a center portion 99. As shown in 
FIGS. 12 and 13, the top portion 97 has a top cover 102 extending between 
edges 103 and 104 which may be of a resilient material having good wear 
characteristics. Under the top cover 102 is a first layer 105 of 
reinforcing cords 106 in edge portions 108 and 109 extending inward from 
edges 103 and 104 to the center portion 99. The cords 106 in the edge 
portions 108 and 109 are laid at a bias angle of about 45 degrees to the 
transverse axis D--D. 
Under the first layer 105 is a second layer 112 of reinforcing cords 113 
coextensive with the cords 106 of the first layer 105. The reinforcing 
cords 113 are laid at an angle of about 45 degrees to the transverse axis 
D--D and at an opposite bias angle to the cords 106 of the first layer 
105. 
Under the second layer 112 is a third layer 115 of transversely extending 
cords 116 between the edges 103 and 104 of the belt 96. Under the third 
layer 115 is a middle cover 118 which is connected at the center portion 
99 to a middle cover 119 of the bottom portion 98. As shown in FIGS. 12, 
13 and 14, the bottom portion 98 in the unstretched condition preferably 
has a width less than the width of the top portion 97. 
Under the middle cover 119 is a fourth layer 122 of reinforcing cords 123 
extending transversely between the edges 103 and 104 of the bottom portion 
98 of the belt 96. Preferably the reinforcing cords 123 are of a high 
modulus material such as steel. 
Under the fourth layer 122 is a fifth layer 124 of reinforcing cords 125 
positioned at a bias angle substantially the same as the bias angle of the 
cords 106 of the first layer 105 and extending from edge-to-edge of the 
center portion 99. Under the fifth layer 124 and coextensive therewith is 
a sixth layer 126 of reinforcing cords 127 laid on a bias at an angle 
similar to the angle of cords 113 of the second layer 112. 
Under the sixth layer 126 is a seventh layer 128 of reinforcing cords 129 
extending transversely between the edges 103 and 104. The cords 129 are 
preferably of high modulus material such as steel. Under the seventh layer 
128 is a bottom cover 130 which extends from edge 103 to edge 104 of the 
bottom portion 98. The transverse cords 129 of the seventh layer 128 and 
cords 123 of the fourth layer 122 are spaced longitudinally of the belt 96 
sufficiently to permit longitudinal stretching of the belt 96 by an 
initial amount of at least 3 percent. During this stretching the cords 106 
and 113 of the first and second layers 105 and 112 interact with the 
transverse cords 116 of the third layer 115 and with the elastomeric 
material of the belt 96 causing the upper surface of the edge portions 108 
and 109 to contract laterally and bend upwardly forming retaining walls 
131 and 132 for containing material being conveyed on a load-carrying belt 
surface 133. Cushioning components 139 are located between the cords of 
the first and second layers 105 and 112, the second and third layers 112 
and 115, the fourth and fifth layers 112 and 124, the fifth and sixth 
layers 124 and 126, and the sixth and seventh layers 126 and 128. 
The belt 96 is fabricated and molded in the flat condition shown in FIGS. 
12 and 13 with the edge portions 108 and 109 of the top portion 97 and 
bottom portion 98 separated by a sheet or plate of material to form slots 
134 and 135 extending to the center portion 99. In operation the belt 96 
is stretchable an initial amount of from 3 to 15 percent due to the 
pantographing of the reinforcing cords 106 of the first layer 105, 
reinforcing cords 113 of the second layer 112, cords 125 of the fifth 
layer 124, and cords 127 of the sixth layer 126. The interaction of the 
cords 106 of the first layer 105 and the cords 113 of the second layer 112 
with the elastomeric material of the belt 96 and the transverse cords 116 
of the third layer 115 during the stretching of the belt causes the edge 
portions 108 and 109 to bend upwardly and form the walls 131 and 132. 
In this embodiment the top cover 102 has a thickness of about 0.07 inches 
at the edge portions 108 and 109 and about 0.13 inches at the center 
portion 99. The reinforcing cords 106 of the first layer 105 and cords 113 
of the second layer 112 may be of polyester and be spaced at about 22 ends 
per inch. The thickness of the first and second layers 105 and 112 may be 
about 0.05 inches each. The third layer 115 may also have reinforcing 
polyester cords 116 spaced at about 22 ends per inch and have a thickness 
of about 0.05 inches. The middle cover 118 for the top portion 97 may have 
a thickness of about 0.07 inches. 
The middle cover 119 of the bottom portion 98 may also have a thickness of 
about 0.07 inches. The transverse reinforcing cords 123 and 129 of the 
fourth and seventh layers 122 and 128 may be steel strands spaced at eight 
ends per inch and having a thickness of about 0.1 inches. The fifth and 
sixth layers 124 and 126 may have reinforcing polyester cords 125 and 127 
spaced at about 22 ends per inch with a thickness of about 0.05 inches for 
each layer. The bottom cover 130 may have a thickness of 0.07 inches. The 
cushioning components 139 may have a thickness depending on the thickness 
of the skim coat on the cords. The cords of polyester have a skim coat of 
a thickness of from about 0.01 to 0.02 inches and the cords of steel have 
a skim coat of from about 0.01 to 0.03 inches. Therefore the total 
thickness of the cushioning components 139 may be from about 0.02 to 0.05 
inches. 
In operation when the belt 96 is directed around a curve the bottom portion 
98 resists transverse deflection of the belt and supports the top portion 
97 which has the walls 131 and 132 for retaining the material on the belt 
surface 133. Due to the stretching of the walls 131 and 132 they will be 
maintained in position even though the elongation of the belt 96 varies 
across the width of the belt. Normally pulleys (not shown) are positioned 
around the edges 103 and 104 of the bottom portion 98 and also under the 
bottom cover 130 to maintain the configuration of the belt 96 around 
curves. 
A belt 136 is shown in FIGS. 15 and 16 which is similar to the belt 96 
shown in FIGS. 12, 13 and 14. However, instead of the fifth and sixth 
layers 124 and 126 of reinforcing cords 123 and 125 being positioned at a 
bias angle to the transverse axis D--D, a separating layer 137 of square 
woven stretch fabric 138 extending between the edges of the center portion 
99' is positioned between the fourth and seventh layers 122' and 128'. The 
stretch fabric 138 of the separating layer 137 has the property of 
stretching a predetermined distance upon initial stretching during 
installation of the belt 136 from about 3 to 15 percent and then has a 
high resistance to further stretching of the belt in operation. In other 
respects the construction of belt 136 to FIGS. 15 and 16 is the same as 
the construction of the belt 96 except there is one less cushioning 
component 139'. In operation the transverse cords of the stretch fabric 
138 and the elastomeric material of the belt 136 interact with the 
reinforcing cords 106' of the first layer 105' and the cords 113' of the 
second layer 112' to bend the edge portions 108' and 109' of the top 
portion 97' upwardly into the shape shown in FIG. 14. 
Referring to FIGS. 17, 18, 19, 20 and 21 a further modification is shown in 
which a belt 142 having a construction shown in greater detail in FIG. 19 
has edge portions 143 and 144 and a center portion 145. The edge portions 
143 and 144 are located between the center portion 145 and edges 146 and 
147 of the belt 142. The edge portions 143 and 144 may be divided into 
outer margins 148 and 149 adjacent the edges 146 and 147 and inner margins 
152 and 153 adjacent the center portion 145. The belt 142 may be of an 
elastomeric material and have a construction similar to the construction 
described hereinabove for the belt 13 shown in FIGS. 4 and 5 except that 
the belt 142 shown in FIG. 19 has edge portions 143 and 144 of greater 
width than the edge portions of the belt 13 by the width of the outer 
margins 148 and 149. Also the third layer 43' extends beyond the ends of 
the first and second layers 32' and 33' so that when the belt 142 is in 
the stretched condition as shown in FIG. 18 the edge portions 143 and 144 
will overlap to enclose the space above the load-carrying belt surface 
31'. With the construction of the belt 142 the thickness of the belt at 
the outer margins 148 and 149 is reduced which also reduces the weight at 
the edges 146 and 147. 
As shown in FIGS. 19 and 20 connecting means such as channels 154 and 155 
are mounted on the bottom cover 53' at the outer margin 149 and ribs 156 
and 157 are mounted on the surface 31' of the top cover 38' at the other 
outer margin 148 for matching engagement upon pressing of the margin 148 
against the margin 149 by suitable means such as rollers 158 and 159. As 
shown in FIG. 17 the rollers 158 and 159 may be mounted on a frame 162 at 
one end of a conveyor 163 close to the tail pulley 164. After the load is 
applied to the belt surface 31' and the belt 142 takes the configuration 
shown in FIG. 18 the ribs 156 and 157 may be pushed into engagement with 
the channels 154 and 155 providing a sealed chamber within the belt for 
conveying material. At the discharge end of the conveyor 163, discharge 
pulley 165 tends to spread the walls 34' and 35' and as shown in FIG. 21 
separating rollers 166 and 167 may be used to assist in this action and 
pull the ribs 156 and 157 out of the channels 154 and 155 so that the 
material conveyed on the surface 31 may be discharged and the return run 
168 carried back to the tail pulley 164 by suitable rollers 169 as shown 
in FIG. 18. The upper run 170 may be supported by support rollers 172. As 
shown in FIG. 18 a roller frame 173 mounted on a supporting surface such 
as the ground or hung from the roof supports the rollers 169 and 172. 
In operation the belt 142 is mounted on the conveyor 163 under tension in a 
similar manner to that described hereinabove for the other modifications. 
As the belt 142 is driven from the tail pulley 164 to the discharge pulley 
165 the rollers 158 and 159 will urge the ribs 156 and 157 into engagement 
with the channels 155 and 154. Then at the discharge end the discharge 
pulley 165 spreading the walls 34' and 35' and supplemented by the 
separating rollers 166 and 167 will pull the ribs 156 and 157 out of the 
channels 154 and 155 and permit the discharge of the material at the 
discharge pulley 165. The elastomeric material of the belt 142 and the 
reinforcing cords may be the same as that described hereinabove for the 
belt 13 of FIGS. 4, 5 and 6. The channels 154 and 155 and ribs 156 and 157 
may be of a resilient material such as nylon which is adhered to the belt 
142 by a suitable adhesive. 
Referring to FIG. 22 a belt 174 has a construction similar to the 
construction of the belt 71' shown in FIG. 11 except that the first layer 
83" and second layer 86" extend over only inner margins 175 and 176 
adjacent the central portion 75". Outer margins 177 and 178 extend beyond 
the ends of the first and second layers 83" and 86" and are adjacent the 
edges 72" and 73" of the belt 174. Also connecting means such as channels 
179 and 182 are mounted on the bottom cover 93" at the outer margin 178 
and ribs 183 and 184 are mounted on the surface 74" of the top cover 82" 
at the outer margin 177 for matching engagement upon pressing of the 
margin 177 against the margin 178 by suitable means such as the rollers 
158 and 159 shown in FIG. 20. 
In operation the belt 174 is mounted on a coveyor similar to the conveyor 
163 shown in FIG. 17 and operated under tension in the same manner as that 
described for the belt 142 shown in FIGS. 17, 18, 19 and 20. 
In FIGS. 19 and 21 the belts 142 and 174 have outer margins 148, 149, 177 
and 178 which are shown substantially equal in width to the corresponding 
inner margins 152, 153, 176 and 175. It is evident that the outer margins 
may have a width substantially greater than the width of the inner margins 
and be in relation to the width of the center portions 145 and 75" so that 
the edges will overlap to enclose the load carried by the belts. 
While certain representative embodiments and details have been shown for 
the purpose of illustrating the invention it will be apparent to those 
skilled in the art that various changes and modifications may be made 
therein without departing from the invention.