Conveyor belt

A conveyor belt, particularly suited to the food processing industry, includes a tension-bearing framework of transversely extending rods connected to tension bearing interconnected links into which is attached a series of loose-fitting modular product support members. The product support modules include forwardly and rearwardly extending link ends such that successive modules are interfitted with one another. Each of the forwardly and rearwardly extending link ends are provided with slotted longitudinal openings through which the transverse rods extend. The distance between a front wall portion defining the slot in a forwardly extending link end and a rear wall portion defining the slot in an associated rearwardly extending link end is greater than the fixed longitudinal spacing spanned by adjacent transverse rods so as to permit some relative longitudinal movement between the conveyor modules and the rods. In addition, at least one of the modules and the rods are provided with standoff elements which define a minimum contact area between the modules and the rods. This limited contact area creates larger openings between the conveyor modules and the rods such that when the conveyor belt is passed through a washing unit, washing sprays can effectively reach all surfaces. In addition, since the conveyor modules are permitted to shift longitudinally relative to the rods, this further enhances the elimination of debris trapping zones such that a highly sanitary conveyor belt arrangement is obtained. In addition, unique end cap members are provided to prevent relative rotation between drive links associated with the conveyor belt and the transverse rods.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to the art of conveyors and, more 
particularly, to a conveyor belt incorporating open conveyor modules which 
are constructed in a manner which enhances cleanability thereof. 
2. Discussion of the Prior Art 
Conveyor belts constructed in various manners are known in the art. Many of 
these conveyor belts are formed from interconnecting symmetric conveyor 
modules by means of a plurality of longitudinally spaced rods which extend 
through respective portions of the modules. The rods are interconnected at 
their respective ends by linkages which cooperate with one or more driving 
units for moving the conveyor belt along a desired path. 
When such conveyor belts are used in particular environments, such as in 
carrying food items for human consumption or other applications requiring 
sanitary operating conditions, the conveyor belts must be cleaned and 
inspected regularly for cleanliness. In many industries, government 
regulations require periodic inspection of conveyor cleanliness. When used 
in such environments, it is commonplace to incorporate a wash unit for the 
conveyor belt along the conveying path, generally in a zone immediately 
adjacent a work station where items are either initially placed on the 
conveyor or removed therefrom. By way of example, FIG. 1 illustrates a 
typical closed cooler compartment 5 used for refrigerating various food 
items placed upon a conveyor belt 8. In order to maximize storage 
capacity, such compartments 5 generally are constructed to permit movement 
of the conveyor belt 8 in a linear direction, as well as taking a helical 
spiralling path, such as generally indicated at 10, wherein successive 
layers of conveyor belt 8 are arranged atop one another. After conveyor 
belt 8 exits compartment 5 and reverses direction to again enter 
compartment 5, conveyor belt 8 proceeds through a washing unit generally 
indicated at 15. Washing unit 15 can spray water or other cleaning 
solutions on either one side or both sides of conveyor belt 8. 
Depending upon the particular construction of the conveyor belt, the 
effectiveness of this cleaning operation can vary. Clearly, a conveyor 
belt formed of open modular units will permit the sanitizing fluid to flow 
therethrough which aids the cleaning process, however, there are various 
hard-to-clean joints, crevices and other debris trapping areas associated 
with known conveyor belts which can lead to unsanitary conditions. In 
addition, the actual material utilized in constructing the conveyor belt 
and the manner in which they are assembled in accordance with the known 
prior art often results in wear debris. The creation of wear debris can be 
an extremely serious problem if, for example, an open conveyor arrangement 
is used with a spiral food processing unit such that any debris from an 
upper conveyor belt layer can fall on food items or the like located on a 
lower conveyor belt layer. This can be a particular problem when the 
conveyor belts are formed entirely from metal with limited clearances 
between relatively moving parts. 
One major debris trapping area associated with known conveyor belts 
incorporating open conveyor modules interconnected by longitudinally 
spaced rods in the manner described above, is the contact zone between the 
rods and front walls of forwardly extending link ends of the conveyor 
modules. In known prior art conveyor belt arrangements, the rods have line 
contact across the entire inner surface of the forwardly and rearwardly 
extending link ends such that the force transmitted through the drive 
units to the rods are transmitted to the modules. This keeps the rod and 
module surface contact areas tightly together, causing frictional wear 
debris when the belt rotates when negotiating vertical change of direction 
pulleys. This tight contact prevents effective removal of any wear debris 
and food particles because the engagement of rod and module blocks one 
side of the assembly to the wash spray from the other side. These surface 
contact areas represent a fair percentage of the overall surface area of 
the modules and therefore the inability to clean in these areas can result 
in less than desirable operating conditions from a sanitary/cleanliness 
standpoint. 
Another problem associated with known conveyor belts that are adapted to 
conform to spiralling paths by the collapsing of the conveyor modules 
progressively towards an inner radial zone is that, since the outer radial 
drive links or modules are fully extended with tension applied thereto and 
the inner radial drive links or modules are collapsed and carry no 
tension, if relative rotation between the drive links or modules carried 
by any given rod is permitted, buckling of the conveyor modules can occur. 
If such buckling occurs in certain environments such as a spiral freezing 
unit, the articles placed on the conveyor belt can take an undesired shape 
and can create problems in packaging of the items. In many known conveyor 
belts utilizing metal drive linkages, heads are formed at the end of the 
rods and these heads are welded to the drive linkages. Unfortunately, due 
to fatigue loading, these welds often break which give rise to the 
problems outlined above, as well as repair costs and undesired down time 
of the conveying unit. Furthermore, these heads often evince burrs or the 
like which can damage the surfaces of frictional drive drums commonly used 
at the inner radial side of such conveyor belts in spiral cooling units. 
Therefore, there exists a need in the art for a conveyor belt that can be 
used over both linear and curvilinear conveying paths which is constructed 
to enhance the cleanability of the conveyor assembly, as well as to 
minimize additional sanitary and operational deficiencies in known 
conveyor belt arrangements. 
SUMMARY OF THE INVENTION 
The present invention provides a conveyor belt, particularly suited to the 
food processing industry, that includes transversely extending rods 
attached to a series of loose-fitting modular product support units. The 
module units include forwardly and rearwardly extending link ends such 
that successive modules are interfitted with one another. Each of the 
forwardly and rearwardly extending link ends are provided with slotted 
longitudinal openings through which the transverse rods extend. The 
distance between a front wall portion of the forwardly extending link end 
and a rear wall portion of the rearwardly extending link end of the slots 
in any given modular section is longer than the fixed longitudinal spacing 
spanned by adjacent transverse rods so as to permit some relative 
longitudinal movement between the conveyor modules and the rods. In 
addition, at least one of the modules and the rods are provided with 
standoff elements which define the contact area between the modules and 
the rods so as to limit this contact area. This limited contact area 
creates larger openings between the conveyor modules and the rods as 
compared to the known prior art such that when the conveyor belt is passed 
through a washing unit, washing fluid can effectively reach all surfaces. 
In addition, since the conveyor modules are permitted to shift 
longitudinally relative to the rods, this further enhances the elimination 
of debris trapping zones such that a highly sanitary conveyor belt 
arrangement is obtained. 
The conveyor belt of the present invention also incorporates a unique 
interconnecting arrangement between the transverse rods and drive links 
associated therewith such that the rods and the drive links are prevented 
from rotating relative to one another, but without the need for welding 
these pieces together. In the preferred embodiment, cap members are 
fixedly secured on the end of the transverse rods. The cap members 
incorporate projections which extend within enlarged areas of the 
apertures through which the transverse rods extend in the edge links. 
These cap members have been found to provide a larger and more suitably 
formed surface for use in combination with frictional inner edge driving 
units used for imparting drive to the conveyor belt through a turn and 
further effectively prevent relative rotation between the transverse rods 
and the edge links such that, when used in combination with a conveyor 
belt that traverses arcuate paths, the inner radial portions of the belt 
are prevented from buckling. 
Additional features and advantages of the conveyor belt assembly of the 
present invention will become more readily apparent from the following 
detailed description of preferred embodiments thereof when taken in 
conjunction with the drawings wherein like reference numerals refer to 
corresponding parts of the several views presented.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With initial reference to FIGS. 2 and 3, a section of the conveyor belt 20 
of the present invention is shown. Conveyor belt 20 includes a plurality 
of modular, item supporting units with modular units 23-25 being 
illustrated in these figures. Each modular unit 23-25 is generally formed 
of a plurality of laterally spaced and forwardly extending link ends 27 
that are joined to a plurality of laterally spaced and rearwardly 
extending link ends 30. As clearly shown in these figures, modular units 
23-25 are interfitted with the rearwardly extending link ends 30 
projecting between the forwardly extending link ends 27 such that the 
forwardly extending link ends 27 and the rearwardly extending link ends 30 
alternate laterally across modular units 23-25. The specific structural 
features of each modular unit 23-25 will be more fully discussed below 
with particular reference to FIGS. 4 and 5. 
As also shown in FIGS. 2 and 3, conveyor belt 20 includes a plurality of 
laterally extending and longitudinally spaced rods 36-38 each of which are 
attached to the forwardly extending link ends 27 of one modular unit and 
the rearwardly extending link ends 30 on an adjacent modular unit. This 
interconnection between rods 36-38 and modular units 23-25 will also be 
more fully detailed below. Each rod 36-38 has opposing end portions 41 and 
42 which extend through drive links 45. Each drive link 45 is secured to a 
respective end portion 41, 42 in a manner which prevents relative rotation 
therebetween by cap members 47. The structure of drive links 45 and cap 
members 47, as well as the manner in which they are interconnected, will 
be more fully outlined hereinafter. 
Specific reference will now be made to FIGS. 2-5 in describing the 
structure of each modular unit 23-25 as illustrated in the preferred 
embodiment shown in these figures. In accordance with this preferred 
embodiment, each modular unit 23-25 constitutes an integrally molded 
plastic member with a repeating sequence of forwardly and rearwardly 
extending link ends 27, 30. One such sequence of link ends for modular 
unit 23, as illustrated in FIG. 4, will now be described in detail and it 
is to be understood that the remaining sections of modular units 23-25 are 
similarly constructed. Each modular unit defines an upper surface 53 and a 
lower surface 55. Upper surface 53 is particularly adapted for supporting 
food items and the like that are transported by means of conveyor belt 20. 
Forwardly extending link end 27 is constituted by a laterally extending 
front wall 58 and a longitudinally spaced crosspiece 60 which are 
interconnected by laterally spaced and longitudinally extending upper 
surface defining side members 63 and 64 as well as a central lower surface 
defining member 66. Rearwardly extending link end 30 is constituted by a 
rear wall 69 and a cross piece 72 which are interconnected by sidewalls 74 
and 75. Sidewalls 74 and 75 are preferably formed with longitudinally 
extending slots 76 and 77 respectively through which an associated one of 
rod 36-38 extends. Forwardly extending link end 27 and rearwardly 
extending link end 30 are interconnected in a joining zone 80. 
As should be clearly evident from these figures, spaced upper surface 
defining side members 63 and 64 of forwardly extending link end 27 are 
vertically spaced from central lower surface defining member 66 so as to 
define a slot 82 therebetween through which an associated one of rods 
36-38 can extend. As will be emphasized below, the distance between a 
forwardmost front wall of slot 82 and the rearwardmost walls of slots 76 
and 77 is greater than the distance spanned by any adjacent pairs of rods 
36-38 such that each modular unit 23-25 is permitted to shift 
longitudinally relative to rods 36-38 by a limited degree. 
As shown in these figures, a standoff 84 in the form of a projection 
extends from an inner lateral surface portion 86 of front wall 58. In the 
preferred embodiment shown, standoff 84 is aligned with central lower 
surface defining member 66. With this construction, as is clearly evident 
from viewing FIG. 2, each rod 36-38 is prevented from engaging a majority 
of the surface area of inner lateral surface portion 86 but instead only 
abuts against standoffs 84. Therefore, gaps (not labeled) are created 
between inner lateral surface portion 86 of a corresponding front wall 58 
of each forwardly extending link end 27 and a respective one of rods 
36-38. As will be emphasized more fully below, the presence of standoffs 
84 and the ability of modular units 23-25 to shift longitudinally relative 
to rods 36-38 greatly enhance the washability of conveyor belt 20 such 
that the highest degree of sanitary conditions can be maintained. 
At this point, it should also be realized that other structures that 
perform the function of standoffs 84 could be provided without departing 
from the spirit of the invention. For instance, each forwardly extending 
link end 27 could be provided with a pair of spaced standoffs located 
below the spaced upper surface defining side members 63 and 64 
respectively which would also function to maintain a gap between a 
substantial surface area of inner lateral surface portion 86 of front wall 
58 and a respective rod 36-38. The presence of a single, centrally located 
standoff 84 is preferred since this minimizes the contact surface area. As 
indicated above, this contact area is a haven for debris that can be 
trapped between the rod and the front wall. Minimizing this contact area, 
as well as permitting the modular units 23-25 to shift relative to rods 
36-38 essentially eliminates debris trapping zones. Again, these aspects 
of the invention will be emphasized more fully below. 
Reference will now be made to FIGS. 6 and 7 in describing the preferred 
construction of each drive link 45 incorporated in the conveyor belt 20 of 
the present invention. Each drive link 45 includes an outer side portion 
93 and an inner side portion 95 which are interconnected by an upper 
connecting portion 97. Outer side portion 93 and inner side portion 95 are 
provided with a pair of opposing slots, 99, 100. Inner side portion 95 is 
also provided with an aperture 102 and outer side portion 93 is provided 
with an enlarged aperture 104. Enlarged aperture 104 is aligned with 
aperture 102 and terminates at a forward portion thereof in a square-off 
end wall 106. In the preferred embodiment shown, both outer side portion 
93 and inner side portion 95 are actually constituted by an aft 
longitudinally extending section 110 within which is provided the 
corresponding one of apertures 102 and 104, an inwardly tapering section 
113 and a fore longitudinally extending section 116 which leads to upper 
connecting portion 97. This construction of drive links 45 is preferred 
since it enables successive drive links to collapse within one another 
such that conveyor belt 20 can negotiate a turn as will also be discussed 
below. 
Reference will now be made to FIGS. 8-10 in describing a preferred 
embodiment for cap members 47. Each cap member 47 includes a head 120 that 
has a smoothly curved annular portion 121. Head 120 is formed with a 
central bore 122 which is adapted to receive a corresponding end portion 
41, 42 of one of rods 36-38. Actually, each cap member 47 can be fixedly 
secured to a respective rod 36-38 by any type of fastening arrangement 
known in the art, such as welding or through the use of adhesives. Each 
cap member 47 is also provided with a depending flange 124. In the 
preferred embodiment, depending flange 124 extends from the outer 
circumferential surface of head 120 to bore 122 in order that depending 
flange 124 is sufficiently sized to prevent breakage even under severe 
fatigue loading. Depending flange 124 therefore includes an arcuate 
central section 127 provided at central bore 122 and then can either taper 
out to the outer circumferential surface of head 120 as shown in FIG. 10 
or the flange could simply extend straight from central bore 122 to the 
outer surface of head 120. 
Reference will now be made to drawings, particularly FIGS. 11 and 12, in 
discussing the various configurations that conveyor belt 20 can take 
during operation thereof given the preferred construction as discussed 
above. FIG. 11 illustrates the relative positioning between the various 
modular units 23-25, rods 36-38 and drive links 45 when conveyor belt 20 
is moving along a straight path. As clearly illustrated, each rod 36-38 
only engages standoffs 84 of forwardly extending link ends 27 in passing 
through slots 82. Each rod 36-38 actually passes through a line of 
forwardly extending link ends 27 as well as a line of rearwardly extending 
link ends 30 and, more particularly, through slots 76, 77 and 82. Each rod 
36-38 then extends through aperture 102 in a respective drive link 45, 
slots 99 and 100 in another drive link 45 and finally through aperture 104 
in the first mentioned drive link. An cap member 47 is provided at each 
end of the respective rods 36-38 with the end of the rods being fixed 
within a respective bore 122 of a given cap member 47. In addition, 
depending flange 124 projects within enlarged aperture 104 in order to 
prevent relative rotation between each drive link 45 and its respective 
rod 36-38. The drive link 45 on the other end of each rod 36-38 is 
likewise secured against relative rotation such that the pair of drive 
links 45 secured to any given rod 36-38 can only rotate in unison. This is 
extremely important in order to prevent the potential of buckling of 
conveyor belt 20 as conveyor belt 20 traverses an arcuate path. When 
traversing an arcuate path, conveyor belt 20 is permitted to collapse so 
that it assumes the position generally shown in FIG. 12. In this Figure, 
the left side end of conveyor belt 20 is fully collapsed and the right 
hand side is still fully extended. 
At this point, it should be realized that conveyor belt 20 is driven, in 
the preferred embodiment, by means of drive sprockets (not shown) which 
directly engage rods 36-38 by sprocket teeth projecting through openings 
in drive links 45. When conveyor belt 20 is driven in a linear path such 
that it assumes the position shown in FIG. 11, drive links 45 on both 
sides of conveyor belt 20 thus carry the entire belt tension. Of course, 
it should be recognized that other drive links could be provided 
intermediate the end of rods 36-38 and, in addition, multiple laterally 
spaced modules could be provided on common rods. However, when conveyor 
belt 20 is used in a helically spiraling conveyor, for example, and 
traverses an arcuate path, it assumes the position shown in FIG. 12, and 
only the drive links 45 on the right-hand side of this figure are 
continuously carrying tension from a drive sprocket, while the cap members 
47 on the left-hand side are driven by frictional engagement with an inner 
rotary drive drum (not shown). Such types of drive sprocket/drum 
arrangements are widely known in the art, do not form part of the present 
invention and therefore have not been illustrated. However, it should be 
noted that the particular construction of conveyor belt 20 advantageously 
prevents undesirable buckling of the conveyor belt 20 when it traverses an 
arcuate path as illustrated in FIG. 12. Since only the right-hand side 
drive links 45 are in tension as opposed to the drive links 45 shown on 
the left-hand side of this Figure, if relative rotation were permitted 
between the left and right-hand drive links 45, the drive links 45 on the 
left-hand side could rotate relative to the drive links on the right-hand 
side and cause undesirable buckling of modular units 23-25 which would 
present an uneven supporting surface for the food items and could also 
deform the food items which makes packaging difficult. By having flange 
124 of cap members 120 extend within drive links 45 and yet be fixedly 
secured to rods 36-38, this relative rotation is prevented. In addition, 
since cap members 47 are pre-formed, they can be readily made with the 
smoothly curved annular portions 121 so that no burrs or rough edges are 
provided which could deform or otherwise alter the functioning 
characteristics of the inner drive drum used to frictionally engage the 
inner radial edge of conveyor belt 20 as conveyor belt 20 traverses an 
arcuate path. In addition, it is possible to form cap members 120 in a 
predetermined configuration such that they cooperate with a specifically 
configured inner drive drum to convey driving force to conveyor belt 20. 
When conveyor belt 20 proceeds through a washing unit, such as that 
discussed above with reference to FIG. 1, conveyor belt 20 will proceed 
along a linear path as represented in FIG. 11. As washing and sanitizing 
fluids are sprayed onto conveyor belt 20, either from one side or both 
sides thereof, the gaps maintained between rods 36-38 and inner lateral 
surface portion 86 of each forwardly extending link end 27 enable superior 
washing of this zone and, in addition, given the fact that the distance 
between a forwardmost portion of slot 82 and rearwardmost portions of 
slots 76 and 77 in the direction of travel of conveyor belt 20 is greater 
than the distance spanned by adjacent pairs of rods 36-38, each modular 
unit 23-25 will be permitted to shift longitudinally relative to rods 
36-38 which further assures the entire zone will be adequately cleansed. 
In addition, this relative shifting between modular units 23-25 and rods 
36-38 further assure that tension provided on each modular unit 23-25 by 
the respective rods 36-38 as conveyor belt 20 traverses along a desired 
path will not be successively transmitted and accumulated between 
successive modular units 23-25. 
In the preferred embodiment described above, each modular unit 23-25 is 
formed from molded plastic. Rods 36-38, drive links 45 and caps members 47 
are preferably formed of metal. In the embodiment illustrated in FIG. 13, 
a modular unit 134 constructed in accordance with the present invention is 
formed from a bent piece of metal. In this embodiment, front walls 135 of 
modular unit 134 are formed with bent or stamped standoffs 136. As in the 
embodiment described above, similar forward and rearward slots would also 
be provided although not shown in this Figure. 
FIGS. 14-16a illustrates another embodiment constructed in accordance with 
the present invention wherein a modular unit 138 cooperates with a rod 141 
provided with projections 143 in order to maintain the desired gap between 
rod 141 and modular unit 138. In this embodiment both modular unit 138 and 
rod 141 are preferably formed from plastic with projections 143 being 
integrally formed with rod 141 and including angled sidewalls 145 and a 
surface bearing top 149. 
FIGS. 16b-17c illustrate additional embodiments for rods that can be 
utilized in the conveyor belt of the present invention. In the embodiment 
of FIG. 16b, a rod 152 is inserted within a sleeve 154 that has 
projections 156. In this embodiment, rod 152 is preferably formed from 
metal and sleeve 154 and projections 156 are preferably integrally molded 
of plastic. In the embodiment illustrated in FIG. 16c, a metal rod is 
provided with a plastic sleeve 162 that is provided with laterally spaced, 
annular projections 164 that are integrally molded with the sleeve 162. 
The embodiments illustrated in FIGS. 17a-17c represent other metal rod 
embodiments constructed with the present invention. In FIGS. 17a, a metal 
rod 168 is formed with stamped projections 170; in FIG. 17b, metal rod 172 
is bent to form standoffs or projections 174; and in FIG. 17c, metal rod 
177 has fixedly secured thereto, by welding or other known fastening 
arrangements, a plurality of laterally spaced beads 178 which function as 
standoffs. 
From the above description, it should be recognized that the conveyor belt 
of the present invention provides for enhanced cleanability such that 
higher standards of sanitary conditions than have heretofore been known in 
this environment can be obtained, as well as a mechanically sound conveyor 
belt construction. Although described with respect to the preferred 
embodiments of the invention, it should be readily understood that changes 
and/or modifications can be made without departing from the spirit of the 
invention. In general, the invention is only intended to be limited by the 
scope of the following claims.