Modular conveyor units and spiral conveyors constructed therefrom

Modular conveyor units are described as including a movable, continuous, spiral conveyor surface mounted on a frame. Spiral conveyors are constructed by stacking one or more of the modular units one atop the other depending upon the height of the spiral conveyor to be constructed, the conveyor surface of each modular unit forming a segment of the thus assembled spiral conveyor. The conveyor surfaces of all modular conveyor units are driven in the same direction to pass articles carried thereon from one unit to the next in the direction in which driven.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an endless conveyor and more particularly to 
vertical, spiral conveyors that may be constructed of modular frames to 
varying heights as determined by the number of modular frames employed. 
2. Description of the Prior Art 
Vertical conveyors that provide a continuous, spiral conveying surface are 
known in the prior art. Such devices may include a flat, continuous belt 
driven from a common power source at spaced points along its length, the 
belt returning upon itself as shown in U.S. Pat. No. 2,267,970. 
Vertical spiral conveyors may also be of the chain type in which flight 
attachments forming the conveying surface are secured to a continuous 
roller chain as shown in U.S. Pat. Nos. 2,564,533 and 2,911,091. As shown 
in U.S. Pat. No. 3,904,025, assigned to the same assignee as this patent 
application, continuous chain type conveyors may be attached to stacked, 
modular frames permitting the construction of conveyors of different 
heights. All of such prior art devices however are subject to the 
limitation of requiring a single, continuous conveyor surface. 
SUMMARY OF THE INVENTION 
The invention is summarized in that a modular, spiral conveyor unit having 
an endless spiral conveyor surface mounted on a frame means, is provided. 
A spiral conveyor assembly is constructed by stacking one or more of the 
modular units, one atop the other to the desired spiral conveyor height. 
The endless conveyor surface of each modular unit forms a curved segment 
of the resulting spiral conveyor such that when all modular conveyor units 
are driven in the same direction articles carried thereon are passed from 
one to the other in the direction to which driven. 
OBJECTS OF THE INVENTION 
An object of the present invention is to construct a spiral conveyor in a 
simple and economical manner. 
A second object of the invention is to arrange a spiral conveyor in modular 
unit permitting the height of the assembly to be varied as needed. 
A further object of this invention is to operate a plurality of modules 
from a common source of power. 
Another object of the invention is to provide a spiral conveyor module with 
a means for maintaining a desirable chain tension. 
An object of the invention is to provide a modular spiral conveyor unit 
with an endless conveyor surface so as to obviate the need for a 
continuous conveyor surface running the length of the assembly. 
These and other objects will be apparent from the drawings and the 
following description of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT 
As illustrated in FIGS. 1 and 2, the present invention is embodied in a 
spiral conveyor constructed of a plurality of modular, self-contained 
spiral conveyor units designated generally by the reference numeral 10. 
The modular units 10 are stacked atop one another on a supporting base 11 
made of heavy structural framing. Each modular conveyor unit 10 includes a 
conveyor chain 12 that forms part of an endless conveyor surface 13 in a 
spiral vertical path around an upper drive sprocket 14 and a lower 
adjustable idler sprocket 15 supported on a modular, octagonal frame 
designated generally as 16. The upper drive sprockets 14 of the modular 
conveyor units 10 are driven by a power chain 17 driven from a common 
power source such as a motor 18 mounted atop the uppermost conveyor module 
10. Alternatively, when three or module units 10 are stacked to form a 
conveyor the motor 18, instead of being mounted atop the assembly, may be 
mounted on the center unit 10 and drive the upper and lower units as well, 
thus splitting the total drive load. Where particularly heavy loads are to 
be conveyed each modular unit 10 may be driven by an independent motor 18. 
The octagonal frames 16 are constructed similarly to the frames shown and 
described in the aforementioned U.S. Pat. No. 3,904,025, incorporated 
herein by reference. Generally, each frame 16 is constructed of eight 
vertical elements 19 formed of angle iron or the like and attached at 
their ends to the corners of similar horizontal upper and lower parallel 
members 20 and 21 having octagonal configurations. Bracing may be provided 
intermediate the upper and lower member as required. 
A tubular bracket 22 extends horizontally from each vertical element 19 
radially away from the center of the octagonal frame. The brackets 22 are 
vertically positioned on successive vertical elements 19 at incrementally 
increased heights, beginning with a bracket near the bottom of a first 
element and ending with a bracket near the top of a last element adjacent 
the first element. 
As shown in FIGS. 3-5, the brackets 22 support upper and lower pairs of 
spaced tracks indicated generally at 23 and 24 curved to form a spiral 
path around the modular frame. Both pairs of upper and lower tracks 23 and 
24 are secured to spaced flanges 26 provided on opposite sides of a 
channel member 27 attached to each bracket 22. The spaced pair of upper 
tracks 23 may be formed of flat, curved plastic plate segments 28, the 
edges 29 of which are detachably received in slots formed in expandible 
wear rods 32 made of plastic or the like. 
Referring to FIG. 5, the wear rods 32 are secured to the plate segment 28 
at various points as by welding and extend short of the end of the plate 
at one end and beyond at the opposite end. This structure facilitates the 
attachment of one plate segment 28 to the other on the flanges 26 of the 
respective channel members 27 to form each of the spaced pair of spiral 
upper tracks 23. 
As shown in FIG. 3, the wear rods 32 on the plate segments 28 forming the 
upper tracks 23 may also be protected from wear by means of flexible, 
semicircular, plastic covers 33 designed to snap over the wear rods after 
the tracks 23 are assembled on the frame. The lower pair of spaced tracks 
24 are assembled of plate segments 28 in the same fashion except only the 
inner adjacent edges of the respective tracks 24 are provided with wear 
rods 32 and plastic covers 33. 
The conveyor chain 12 travels around each bracket 22 between the spaced 
upright flanges 26 on opposite sides of the channel member 27. As is shown 
in FIG. 3 the conveyor chain 12 may be of a conventional pin and roller 
link construction. As is known from the prior art, flight attachments 38 
may be secured to the links of the chain to make up the endless conveyor 
surface 13. 
Depending legs 39 and projecting feet 41 on the flight attachments 38 form 
grooves that slidably receive the adjacent, plastic covered edges of the 
spaced tracks 23 and 24, the underside of the flight attachments being 
supported upon the wear surfaces on the upper tracks 23. Brackets 22 may 
also be provided with guides 43 on opposite sides of the spaced pair of 
tracks 23 to prevent articles such as cartons carried on the modular 
conveyor units 10 from falling off. 
The continuous conveyor chain 12 with flight attachments 38 secured thereto 
travels around the upper drive sprocket 14 and lower idler sprocket 16 of 
each modular conveyor unit 10 to complete one spiral loop around the 
vertical, longitudinal axis of the unit. As shown in FIG. 1, the upper 
drive sprocket 14 is spaced from the idler sprocket 15 of the modular 
conveyor unit above it so that the endless conveyor surface 13 carried by 
adjacent units 10 may freely pass around the respective sprockets without 
interference to the other. 
As shown in FIG. 2, the drive sprocket 14 is affixed to an axle 44 
supported in bearings 46 attached to the opposite legs of a U-shaped 
bracket 48 secured by welding or suitable fasteners to a support arm 52 
formed of angle iron. The arm 52 projects from one side of the upper 
member 20, FIG. 1, parallel to and horizontally offset from a horizontal 
centerline passing through the centers of the one side and its opposite 
side of the octagonal configuration formed by the upper member 20. Power 
is transferred from motor 18 via chain 17 to a sprocket 55 at each module, 
each sprocket 55 driving its respective sprocket 14 through the axle 44 on 
which both sprockets are mounted. 
Referring to FIGS. 6 and 7, the idler sprocket 15 of each modular unit 10 
is mounted on a similar support arm 56 attached to the lower member 21 
directly below the upper member 20. Support arm 56 carries idler sprocket 
15 and extends parallel with support arm 52. The respective idler and 
drive sprockets 15 and 14 of each modular unit 19 are thus horizontally 
offset from vertical lines through each other for the reasons previously 
described. 
The idler sprocket 15, unlike the drive sprocket 14, is carried on L-shaped 
brackets 58 adjustably secured to similar brackets 59 rigidly secured to a 
flange 57 of support 56. The brackets 58 and 59 are slidably secured 
together by means of headed bolts 60 that extend through adjacent and 
correspondingly spaced slots formed in the brackets which provide positive 
stops to limit the maximum slack in the chain. 
The support arm 56 includes a U-shaped member 61 attached as by welding to 
the flange 57 of support 56 on the side opposite to that which brackets 59 
are attached, confining compression springs 62 that extend through holes 
in the flange 57 to engage the brackets 58. The springs 62 are captured in 
this position by threaded bolts 63 that pass through the member 61, the 
flange, and brackets 58 and hold the chain under spring tension for a 
smooth conveyor operation. 
The minimum slack or maximum tension in the chain is adjusted by turning 
the heads 64 of bolts 63 relative to the nuts 65, the compression springs 
62 urging the brackets 58 relative to brackets 59 to the limit of the 
positive stop provided by the bolts 63. This permits an even tension to be 
maintained in the conveyor chain 12 carried on the idler sprocket 16 and 
provides for a smooth running endless conveyor surface 13. 
The physical dimensions such as the diameter and height of the modular 
self-contained conveyor units 10 embodying the invention may be changed as 
desired, the number of such units stacked one upon the other determining 
the height of the spiral conveyor so constructed. Once vertically 
assembled the units 10 are secured together by any suitable fastener means 
and the common power source (motor 18) is mounted to a cross member 
affixed to the top of the uppermost unit as shown in FIG. 1. The drive 
chain 17 is then connected to the axles 44 of the respective drive 
sprockets 14 so all are driven simultaneously in the same direction. 
As the spiral conveyor loop of the lower unit 10 ends near where that of 
the unit 10 immediately above it begins, articles are carried from one to 
the other of the modular conveyor units 10 when all are driven in the same 
direction. Each modular unit 10 provides a segment of the total spiral 
conveying surface. Therefore, the height of a spiral conveyor constructed 
of such modular units 10 can be readily varied by adding or removing units 
without the need for changing the conveying surface as in prior art 
devices. 
Preferably, the endless conveyor surface 13 of each modular unit 100 
completes a spiral path 360.degree. around the frame 16, or an integral 
multiple thereof, permitting all drive sprockets 14, of stacked units 10 
to be positioned one above the other. This in turn permits all sprockets 
14 to be driven by a single and common power source (motor 18) with a 
minimum of complexity. 
The above described invention presents the advantage of allowing rapid 
assembly of modules, since the conveyor surfaces are containing on each 
module, and need not be fitted to the assembled modular frames. A further 
advantage provided is that the conveyor surfaces may be kept under proper 
tension at all times without need for continuous adjustment. 
The endless conveyor surface 13 of each unit 10 may however, complete a 
path of less than 360.degree. in which event the drive sprockets 14 of 
stacked units 10 will be offset from one another. In this event separate 
conveyor chain drive motors may be provided for each module 10. 
Irrespective of the degree of turn of each endless conveyor surface 13 one 
must end near where the next above begins in order to form a vertical 
spiral conveyor. 
Inasmuch as the present invention is subject to many variations, 
modifications and changes in detail, it is intended that all matter 
contained in the foregoing description or shown in the accompanying 
drawings, shall be interpreted as illustrative and not in a limiting 
sense.