WO1991004208A1 - Stacking belt drive system - Google Patents

Abstract

A support system (20) for the stacked interior edges (50) of a helical portion (24) of an endless belt conveyor (22). The system includes a continuous rail (70) at the bottom tier of the helical portion (24). A series of trolleys (72) ride on their flanged wheeels (82, 84) on this rail (70). The trolleys (72) are directly driven therealong by a rotatable inner drive cage (64) which drives the helical belt (22) portion through its links (56). The belt (22) as it enters the helical portion rides on the trolleys (72) up the helical rail (70) and on to a short support transittion plate (108). The rail (70, 78) and trolleys (72) then drop sharply to pick up the next incoming belt portion (22), and the partially self-supporting belt continues up its helical path (24). This rotatable drive cage (64) is preferably positioned within the helical portion (24) to drive trolleys (72) on the inside edge of the belt (22). Trolleys (208) can also be provided to support or drive the outer edge of the belt (202), where the belt is a double-edge stacking belt (202). A hubless rotatable ring cage preferably drives the outer trolleys (208), and the inner and outer cages are preferably rotated by the same motor througha drive chain system (220). Alternatively, the outer trolleys (208) can be pulled along through the conveyor belt (220), the outer cage can be omitted and the outer trolleys (208) driven directly by the inner drive cage (210), or a C-shaped guide channel (330) drive provided in lieu of the drive cage.

Description

STACKING BELT DRIVE SYSTEM

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part (CIP) of copending applications (1) 07/526,762, filed May 23, 1990, which is a continuation of Serial No. 07/406,109, filed September 12, 1989 (and which has a sister appli¬ cation Serial No. 07/406,348, filed September 12, 1989, and which issued September 11, 1990 as U.S. Patent 4,955,465 ('465)), now aban¬ doned, which is a CIP of copending application Serial No. 07/224,696 0696), filed July 27, 1988, which issued July 10, 1990 as U.S. Patent 4,940,133, and which is a CIP of copending applications (a) Serial No. 07/171,390, filed March 21, 1988, which in turn is a CIP of application Serial No. 07/083,272, filed August 10, 1987, now abandoned, and (b) Serial No. 07/213,171, filed June 29, 1988, and which issued August 28, 1990 as U.S. Patent 4,951,807, and which in turn is a CIP of the '390 and '272 applications, (2) the '696 application, and (3) Serial No. 07/472,060, filed January 30, 1990. (A corresponding European Patent Application No. 88,307,384.3 was published as Publication No. 0.303.457.A1, and the entire contents of this publication and any other publications, applications or patents mentioned anywhere in this disclosure are hereby incorporated by reference.) BACKGROUND OF THE INVENTION

This invention relates to endless conveyor belt systems wherein the belts are driven in a helical path. These systems convey products of various kinds through a confined space for a certain amount of time for treating the products, as by heating, drying, cooling or freez¬ ing them. Since these systems satisfy rigorous hygiene requirements, they are well suited for handling food products. This invention more particularly relates to both single edge and double edge self -stacking helical conveyor belt systems. The conveyor belt as it travels along the superimposed, heli¬ cally extending belt tiers can be self-supporting on one or both of its edges. By having the spiral conveyor belt being self-supporting, framework across the belt for supporting the belt is not needed. This framework occupies valuable product carrying space. Eliminating the framework reduces the height between the tiers and the overall height of the spiral. An example of a conveying system wherein the belt is self-supporting on both edges is that shown in U.S. Patent 3,938,651 0651), whose entire contents are hereby incorporated by reference. A disadvantage of having the belt being self -supported on the outside edge however is that it is not open at the outside to pro¬ vide good circulation with cooling or freezing air. Thus, another design is shown in European Patent Application Publication No. 0.293.095.A1 of Cawley, whose entire contents are hereby incorpo¬ rated by reference. In this application, the tiers at the outside of the helix are supported by a fixed helical guide which is open between the tiers and the inside of the helical belt is sel -supported by upstanding spacer plates mounted to articulated belt links.

When the belt is self-supporting on one or both sides, structure is needed to support the lowermost tier of the belt at those edges. The angle or pitch of this lower support tier determines the pitch of the rest of the helical conveying path. A known way for supporting the lowermost tier, which is disclosed in the '651 patent, provides a supplemental conveyor which drives the lowermost tier. Another known way for supporting the lowermost tier, which is disclosed in the Cawley application, supports the tier on a stationary support which may include small rollers.

The conveyor belt through the helical portion thereof can be driven by a drive cage centrally located within the helical belt. The cage has a plurality of vertical driving bars which engage the heads of the bars of the belt and when rotated by an electric motor drive the belt along its helical path. Supplemental positive drives are provided at the inlet and outlet of the conveyor belt relative to the helical portion, that is at both ends of the belt return path, and synchronized with the drive of the drive cage for smooth even belt travel. Such a positive drive helical conveyor system is shown for example in U.S. Patent 4,741,430, which is also hereby incorporated by reference in its entirety. See also U.S. Patent 4,858,750. SUMMARY OF THE INVENTION

Accordingly, a principal object of the present invention is to provide an improved helical conveyor system.

Another object of the present invention is to provide a more compact helical conveyor system, especially one which is used to cool or freeze the conveyed products.

A further object of the present invention is to provide an improved support system for the lowest tier of a helical conveying system whose inner helical belt edge is self-supporting.

A still further object of the present invention is to provide an improved drive and support system for a helical, double-edge stacking conveyor belt.

Directed to achieving these objects, an improved helical con¬ veying system is herein provided. The helical portion of the endless belt for this system is supported at its outer edge by a helical rail. The inner edge is self-supporting, and an improved system for sup¬ porting the lowermost tier thereof is herein disclosed. The support system includes a continuous rail helically formed through between approximately two hundred and seventy and three hundred a::d fifty degrees of its path, or about three hundred degrees for a five foot diameter rail, and having a short downwardly sloping portion smoothly connecting the lower and upper ends thereof. A series of trolleys ride on their flanged wheels on this rail about its continuous circuit. The trolleys are connected to the drive cage so that when the drive cage rotates and drives the conveyor belt along its helical path, the trol¬ leys are driven along the rail. The axis of one of the wheels of each of the trolleys extends a distance from the adjacent end of the sup¬ port trolley portion so that when the trolley moves over the upper¬ most end of the connector rail portion the main trolley portion does not rise to cause the conveyor belt to bump up.

In a helical conveyor wherein the belt enters the helix at the bottom, the trolleys carry the conveyor belt up and along the helical path. When the trolleys reach the upper end of their helical rail path they drop off down the connector portion and the conveyor belt is carried a short distance then by a support transition plate. The belt slides off of the transition plate and is self-supporting at its inner edge for the remainder of the helical path. Alternatively, in a helical conveyor of this invention wherein the belt enters the helix at the top, the belt is self-supporting at its inner edge until it reaches the lowest tier. The belt then slides onto the transition plate as the trol¬ leys reach the lower end of their helical rail path and rise up the con¬ nector portion. The belt slides off the transition plate onto the trol¬ leys at the upper end of their helical rail path, and the trolleys carry the belt down and along the helical rail path until the belt exits the helix.

The conveyor belt as it leaves the helical path is carried away by end support rails to the return path portion. The slack is kept out of the return path portion by an off-center, horizontal tensioning means. If the return path is relatively short only a single supplemen¬ tal drive for the conveyor may be needed, and it is positioned just prior to the tensioning means.

For a helical double-edge stacking conveying system of the genre discussed in the '651 patent an outside helical rail for the lower¬ most outer tier is herein provided. This rail similarly has a major upwardly sloping portion and a short more steeply sloping downward portion. A similar outer wheeled dolly or trolley system rides on this outer rail and supports the outer edge of the lowest tier of the double- edge stacking belt. A hubless outer drive cage is mounted outside and no higher than the outside tier rail. The outside cage is rotated through a drive chain simultaneously with and through the same shaft-sprocket assembly as the inner drive cage. The outside cage similarly has vertical drive bars. Connector bars are affixed at their upper ends to the inside surfaces of the outside dollies and are slidably secured at their lower ends to the vertical drive bars to be driven thereby circularly about the vertical axis, while still allowing the outer dollies to move up and down along the slopes of the outer helical rail. In lieu of the more complicated outside drive cage, a C-channel drive block assembly can be used.

Other objects and advantages of the present invention will become more apparent to those persons having ordinary skill in the art to which the present invention pertains from the foregoing description taken in conjunction with accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is an elevational view of a first conveying system of the present invention.

Figure 2 is a longitudinal sectional view of the system of Figure 1.

Figure 3 is an enlarged fragmentary view of a portion of the trolley assembly of the system of Figure 1.

Figure 4 is a top plan view of the trolley assembly of Figure 3.

Figure 5 is an enlarged elevational view of the slack take-out system of the system of Figure 1, with the belt and anti-torsion wheels thereof omitted for the sake of clarity.

Figure 6 is a top plan view of the slack take-out system of Figure 5, with the belt thereof omitted for the sake of clarity.

Figure 7 is an enlarged cross-sectional view taken on line 7-7 of Figure 1.

Figure 8 is an enlarged, fragmentary plan view of a portion of the conveyor belt of the system of Figure 1.

Figure 9 is an end elevational view of the trolley support rail of the system of Figure 1 and shown in isolation.

Figure 10 is a top plan view of an alternative, preferred spacer plate for the conveyor belt of Figure 8.

Figure 11 is a side elevational view of the spacer plate of Figure 10.

Figure 12 is an end elevational view of the spacer plate of Figure 10.

Figure 13 is a bottom plan view of a portion of a conveyor belt similar to that of Figure 8 and using the spacer plate of Figures 10-12.

Figure 14 is a top plan view of a second conveying system of the present invention. Figure 15 is an elevational view of the system of Figure 14.

Figure 16 is an enlarged cross-sectional view taken on line 16-16 of Figure 14.

Figure 17 is a view similar to that of Figure 16 showing an alternative preferred outer drive arrangement of the second convey¬ ing system of Figure 14.

Figure 18 is an enlarged perspective view of the connecting assembly of Figure 17.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

A conveying system of the present invention is illustrated in Figure 1 generally at 20. Conveying system 20 includes a conveyor belt 22 which is supported and driven to travel through a helical por¬ tion 24 and a return portion 26 of its endless path. The belt 22 after traveling through the helical portion 24 leaves the path via an exit rail assembly shown generally at 28. It then travels around a supple¬ mental drive sprocket 30 driven by a motor 32. The chain 34 of this supplemental drive as shown in dotted lines in Figure 1 defines a long oval loop from the motor 32 to the drive sprocket 30. The belt 22 then is flipped over by the sprocket 30 and passes around a slack take¬ out system shown generally at 36 and thereby flipped back over, trav¬ els horizontally a distance, then vertically along a pair of idler wheels 38, 40 and then horizontally the length of the conveying system 20 where it travels up and around another idler wheel 42 to enter the bottom tier support system shown generally at 44. Product loading and unloading stations for the belt can be located generally at 46 and 48, respectively. It is also within the scope of this invention to reverse the positions of the loading and unloading stations and have the belt (and products thereon) travel down the helical path.

The belt 22 is preferably a single pitch design as disclosed in the '384.3 European application and can be an adaptation of the "Space Saver Omni-Grid Belt" introduced in January of 1989 by Ashworth Bros., Inc. As will be described later and is disclosed Euro¬ pean application, the belt 22 is self-supporting on its inner edge on a series of stacker plates 50. By stacking the belt 22 on the inside, no member coming across the belt 22 to support it and thereby reduce the product carrying vertical space of the belt is needed. The belt 22 is supported along the helical path 24 at its outer edge by a helix rail 52. The helix rail 52, which can be about two hundred feet long, is attached to the upright framework 54 of the conveyor system. Sup¬ port for the stacked inner belt 22 is provided at the lowest tier of the inner belt edge by the support system 44.

At the inside, the tiers are supported one on the other by an arrangement which includes articulated links 56 at least some of which include the upstanding plate spacers or stacker plates 50. The tops 58 of the plates 50 at any one tier engage the underside of the links or plates associated with the tier immediately above. The inside edge of the conveyor belt 22 is driven up and along its helical path by the centrally-located drive cage shown generally at 60 and as is dis¬ closed for example in the previously-mentioned '430 patent or the '384.3 application. As disclosed therein, the belt in the sp . 1 is driven along only the inside edge of the belt and the outside edge of the belt expands while the inside edge does not collapse. Significant belt tension thus can be created along the inside edge. The frame¬ work 54 is shown along the outer edge of Figure 2. A round mechani¬ cal tubing 62 rotatable within a sleeve 64 in the framework defines the vertical axis about which the drive cage 60 is rotatable. The drive cage 60 includes a plurality of circumf erentially spaced, vertical drive bars 64. The drive bars 64 are driven through suitable linkages and an electric motor about this vertical axis. The cage 60 is advan¬ tageous as it adds stability to the conveying system 20 and makes it less likely for the whole stack of conveyor belt in the helical path 24 to topple over. Ribs in the centers of the bars 64 engage the ends of the rods 69 of the belt 22 to drive the belt up the helical path 24 in a known manner.

The support system 44 is comprised of three components, namely, a support rail as best shown in isolation in Figure 9 at 70, a series of trolleys shown generally at 72 in Figures 2, 3 and 4, and a connector assembly shown generally at 74 in Figure 4. The connector assembly 74 drivingly connects the trolleys 72 to the drive bars 64 of the drive cage 60 such that when the drive cage is rotated the trolleys are driven along the rail 70. The rail 70 defines a complete circle about the vertical axis of the drive cage 60 and consists of two parts. The first part 76 travels the major part of the turn of between two hundred and seventy and three hundred and sixty degrees and is shaped as an upwardly spiraling helix. The second minor part 78 defines a sloping transition section whereon the trolleys descend to the lower starting point of the helix. The rail 70 comprised of these first and second parts 76 and 78 is supported on stanchions 80.

Front and rear wheels 82, 84 of the trolley 72 support the sup¬ port member 86 of the trolley. The wheels 82, 84 have flanges 88 which lap over the sides of the flat rail 70 to hold the wheels on the rail. The connector assembly 74, as best shown in Figure 4, includes a pair of posts 90, 92 spaced horizontally, extending out from the trol¬ ley support member 86 and positioned adjacent and between adjacent drive bars 64 of the drive cage 60. A slider bar 94 secured to the ends of both of these posts 90, 92 by fasteners 93 slidingly engages the inner surfaces of the vertical drive bars 64. Thus, the drive cage 60 as it rotates drives the trolleys 72 along the entire circuit of the rail 70 while allowing the trolleys to travel up and down along the helical and sloping portions 76, 78 of the rail 70. The trolleys 72 slide up and down on the drive bars 64, and thus the bars 64 keep the trolleys 72 from falling off of the rail 70.

The trolleys 72 pivot as they drop down about their rear axles 100. When the trolley 72 turns about the pivot point of the rear axle 100 any portion of the trolley located behind that point moves ini¬ tially up instead of down thereby causing a bump in the belt 22 every time the front of the trolley drops down and the back kicks up. To prevent the rear portion of the conveyor belt support member 86 from bumping up as the trolley 72 travels down the connector rail portion 78 the rear axle 100 is positioned by the bracket 102 behind the rearmost portion of the support member.

As one of the trolleys 72 is driven to the starting point of the helical rail portion 76 it picks up the corresponding portion of the conveyor belt 22 and carries it to the top of the helical portion 76. The trolley 72 then drops down along the connector rail portion 78, and the conveyor belt 22 slides onto the transition plate, which is shown generally at 106 in Figure 3. The plate 106 includes an upper plate member 108 held above the trolleys 72 by a pair of support posts 110 secured at the lower ends to a curved plate 111 welded to the stanchions 80. The conveyor belt 22 as it next leaves the transition plate 106 is self-supporting along its inner edge on its support plates 50 as it travels up the helical path driven by the drive cage 60.

As the conveyor belt 22 leaves the top end of the helical path 24 it is lifted thereoff by the rail assembly 28. In particular, Figure 7 shows the conveyor belt 22 supported as it exits the helical path 24 on rail assembly 28. On the left-hand side, it is supported with short tubes 114 welded to the conveyor framework. Wear strips 116, 118 are provided on the lift rails 120, 122 supported inside of the tubes 114 for supporting thereon the T-shaped stacker plates 50 of the conveyor belt 22. By stacking the belt 22 up until it exits it must cross back over the tier below. Thus, the belt 22 cannot be supported from underneath since it is still over the tier below. It also cannot stack further since it will pull right off the stacks. Thus, after pulling it off the stack, it must be supported until it passes across the tier beneath and away from the stack. This support is provided according to this invention underneath by strips 116, 118 on the rails 120, 122. This is similar to the way that some barn doors slide, except that instead of a wheel on each side there is a tab riding on plastic. The exit rail assembly 28 maintains a clear space between one tier and the next, and no product conveying space is thereby lost. The opposite edge of the conveyor belt 22 rides on a bar 124 of the helix rail 52 having a plastic cap 126. The bar 124 extends up from the end of a long rod 128 threaded through a frame 129.

The slack is taken out of the conveyor belt 22 as it travels along the return path 26 by the slack take-out system 36 shown in Figures 1, 5 and 6. The belt 22 as it travels around the half-circle shaped members 130, 132, as shown in Figures 1, 5 and 6, carries ten¬ sion on one side and is slack on the other side. This is because the belt 22, which is driven only along its inside edge, changes shape as it goes from running straight to around a lateral curve such as in a spi¬ ral. Also, the belt 22 is in a reverse bend here so that the plates 50 instead of folding out as they are going around are crowded in towards one another. The present take-up system 36 applies off-set back ten¬ sion to the belt 22 to take this slack out.

At the half-circle shaped members 130, 132 the belt 22 thus makes a backwards bend. An idling wheel or a sprocket will not fit in the edge of the belt since the plates 50 are in the way. Instead the present system 36 includes the two half-circle groove members 130, 132 and a framework 140 to hold the members apart a distance slightly greater than the width of the belt 22. The grooves are coated with a strip 142 (or spaced wear blocks) of friction reducing plastic so that the belt 22 can travel freely in them. The framework 140 can move horizontally on a pair of attached wheels 144, 146 rolling on a fixed rail 148.

A tension cable 150 is hooked to the C-shaped member 132 on the belt tension side by a cable loop 151 formed by a wire rope clip 152 and looping over lateral pipe 153. The cable 150 extends over sheaves 155 and 156 secured to cross-bar 157 to a downwardly- depending weight 160, whose weight is adjustable through material ports 161a and 161b, where it hooks to an eye bolt 162 attached to the top of the weight. The weight 160 acting through the cable 150 pulls the C-shaped members 130, 132 horizontally against the overlying belt 22 thereby tensioning the belt. In other words, when slack occurs in the belt 22 the C-shaped members 130, 132 are moved on their wheels 144, 146 to the right as depicted in Figures 5 and 6, and when the slack disappears movement is to the left. The attachment of the cable loop 152 to the C-shaped member 132 is above the rolling sur¬ face 163 of the wheels 140, 146 on the rail 148. To prevent tipping (in a clockwise direction as can be understood from Figure 5) a third wheel 164 is attached to the framework 140 and rides underneath and presses against the lower surface of the rail 148.

The cable 150 is attached to the framework 140 offset from the centerline thereof to accommodate the greater tension on one belt edge. The force applied by weight 160 along the line of cable 150 thus provides a balancing force aligned with the tension carrying portion of the belt. Ideally, the belt tension is shared equally between the two rows of generally U-shaped inside links, which are best shown in Figures 8 and 13. In practice however, slight variations in the manu¬ facture of the links 56 can make for an uneven and varying sharing of the tension by the belt when operated. If the cable 150 is not per¬ fectly aligned with the effective line of belt tension force, twisting forces are exerted on framework 140. These forces are handled according to the invention by leading and trailing anti-torsion wheels 166, 168 extended out from the C-shaped members 130, 132 and riding on the fixed rails, as can be seen in Figure 6.

The conveyor belt 22 itself as shown best in Figure 8 includes the transverse rods 69 interconnected by links 56 disposed along oppo¬ site transverse edges of the belt. The preferred "shingling" of the bar links 172 is illustrated in F igure 8. Two rows of spacer plates 50 are sandwiched in the links. The plates 50 are bent over forming tabs 174, which define the plate tops 58, on which the next layer of belt 22 is stacked in the helical path 24. The two rows of links 56, on the left-hand side of Figure 8, are close together.

Thus, an alternative preferred configuration of the plates 50 has the bottom tab 176 thereof bent around in an angled C-shaped pattern or footprint 178 as shown in Figures 10-13. This provides a bigger footprint, as can be best appreciated from Figure 13, than just an edge view of a piece of sheet metal to help hold the plate 50 upright, and the C-shaped footprint 178 thereby makes the spacer plates 50 more self-supporting. The two rows of inside links 56 accordingly need not be squeezed so tightly together to hold the plates 50 upright. This C-shaped footprint 178 also makes it easier to clean the belt 22. The ends of the rods 69 pass through the through- holes 180 in the tabs, as shown in Figures 11 and 13. Spacer plates with this C-shaped footprint 178 configuration can also be used in two-edged stacking belts.

These stacked plates 50 support the entire belt 22 at the inside of the helical path 24 without the need for a separate inner support rail. The tension in this belt 22 is carried by the inner edge links 56 which do not collapse when the belt goes into a turn. The outer edge of the belt 22 which is supported by the helix rail 52 opens up as the belt 22 goes into the turn but remains slightly loose and does not carry the belt tension. A snug fit of the belt's inner diameter around the driving drum cage 60 and an easier transition of the stacking inner edge as it enters and leaves the helical path 24 are thereby provided.

The conveying system of Figures 14-16 shown generally at 200 is particularly adapted for stacking, driving and supporting a double- edge belt 202, such as is shown in the previously-mentioned '651 appli¬ cation. Additional examples of belt systems both single and double- edge stacking and various preferred embodiments of the stacking plates therefor are illustrated in the '060 application, in the applica¬ tion filed concurrently herewith entitled "Conveyor Belt With Stack¬ ing Plates", and assigned attorney docket No. 0120.028855, and those described in "Ashworth Does It Again!-NP89", Ashworth Bros., Inc., 1989 and 1990, and Ashworth Bulletin No. SR80 (Rev/8/83) entitled "An Introduction to Small Radius Omniflex and Small Radius Omni- Grid". As can be appreciated by those skilled in the art, many differ¬ ent types of conveyor belt systems formed of metal, plastic and other materials can be adapted for use in the conveyance system of the present invention. One preferred example of a belt 202 which can be used is the Space Saver Omni-Grid Belt which has a non-collapsing inside edge. A preferred stacking plate would be that with an S-shaped foot wherein the tails of the S are welded back to the plate, as disclosed in the above-mentioned concurrently-filed application, and which gives the plate's pad or bottom base added rigidity. The belt can further be equipped with overlay or mesh systems such as is shown in the copending application Serial No. 07/472,062, filed January 30, 1990.

The double-edge stacking conveyor system 200 of Figures 14-17 essentially takes the single-edge system (20) of Figures 1-9 and adds an outer drive cage 204 outside of the inner drive cage 206 (or 60) and at the outer edge of the conveyor belt 202. A system of outer trolleys or dollies 208 similar to the inside dollies 210 are provided and run on a similar outer helical rail 209. Although an outer drive cage 204 or other direct drive system for the outer trolleys 208 is not absolutely required and thus the outer trolleys could roll freely, this arrangement would most likely increase the lag on the outside edge of the conveyor belt 202, inasmuch as the outer trolleys 208 would actually be pulled along only by the inside of belt 202.

Accordingly, the outer drive cage 204 is provided by system 200 and, as will be explained in detail later, is driven simultaneously with the inner drive cage 206 by the same motor 218 and through a gearing drive chain arrangement shown generally at 220. The motor 218 is approximately a five horsepower motor which is connected to an adjacent gear box 222 as shown for example in Figure i5. The power is distributed from the gear box 222 through chains 224 to a large sprocket 226, and the chain that goes over to the large sprocket 226 drives the inside cage 206. The sprocket 226 is shown at the bottom central portion of Figure 15 under the small central trolley shown in side view. The sprocket 232 that goes to the outside is connected by a jack shaft 234 to a sprocket 242 which then drives the outside cage 204. The jack shaft 234 is depicted underneath the take-up system shown generally at 242 in Figure 15 similar to the previously- described take-up system 36. Although depicted in the elevational view 15 as being directly underneath, in actuality it is spaced there¬ from, as better shown in Figure 14.

The vertical shaft 234 has three sprockets on it. The center sprocket 246 accepts the drive power coming in from the gear box 222. Above that sprocket 246 is a second sprocket 242 which drives the chain 250 which pulls the outside cage 204 and below the center is the third sprocket 252 which goes over by chain 253 to the auxiliary gear box 254 and drives the belt over near the take-up. The sprockets are sized so that the two associated with the trolley system, the one on the inside edge of the belt and the one on the outside edge of the belt 202, are running at essentially the same speed. The one on the outside runs a slight amount faster than the belt 202 because of the greater circumferential distance it must travel. The inside trolley system 210, its cage 206 and adjacent portion of the belt 202 all run at the same speed because the cage positively drives the belt and it is positively connected to the inside trolley, which is running at that speed also. The outside trolleys 208 travel slightly faster than the inside trolleys 210, as previously mentioned, because of their greater circumferential travel distance and even if they over drive the out¬ side belt edge a percentage or two this is not critical to effective belt function. In other words, the speed at the belt 202 is slightly differ¬ ent across its width and is going faster on the outside.

Referring to Figure 15 on the very right side and in vertical alignment in that view, there are three sprockets, wheels or rollers 260, 262, 264. These guide the belt 202 through the take-up 240. The top one 260 is the auxiliary drive. The diagonal dotted line 268 repre¬ sents the chain going up to it, and it is exactly synchronized with the cage by an auxiliary drive and in initely adjustable gear box and trans¬ mission 269 as shown in Figure 14. The upper box-like portion 270 thereof illustrates a right angle device which takes the vertical rota¬ tion and converts it to a horizontal rotation. The horizontal coupling 272 goes into that next "rectangle" 276 which represents an infinitely adjustable variable speed transmission which can be adjusted to obtain the exact synchronization.

The double-edge stacking belt 202 is thus stacked on the outside edge when in the helical portion of its continuous path and preferably is also driven and supported on the outside edge. If it were not driven, the mere friction of its heavy weight on the rail would be excessive, as previously mentioned. It is noted though that most, a minimum of three-quarters, of the power for driving the belt 202 along the helix comes from the inside 206 and not the outside cage 204. The outer trolleys 208 are being driven more or less simply to support the outside edge moving with the belt 202 to give the belt on the outside edge a rolling support rather than a f rictional support.

The bottom outer helical support tier at 209, as shown in Fig¬ ures 16 and 17, for example, has a longer transition than that of the inside tier, and the outer trolleys 208 must come around and drop underneath at point 209a the incoming belt 202. The path underneath the incoming belt 202 is longer on the outside than on the inside because there is a longer transition on the outside. The outer and inner trolleys or dollies 208, 210 are conceptionally the same. The point of attachment to the respective cages 204, 206 differs, how¬ ever. The outside cage 204 must always remain lower (Figures 15 and 16) than the outer trolleys 208 so that the incoming belt 202 does not impact the outside cage. Thus, the cage 204 driving the trolley 208 and the systems of the trolleys actually fit above the cage, and there is not a direct connection from the cage and to the trolley. Rather, an offset connection is needed as shown in Figures 16-18 as shown at 280. Referring to Figure 16 it is seen that the double-edge stacking belt 202, with stacking plate 202a, is considerably higher than the tops of the cage bars 204a wherein the tops of the cage bars are rep¬ resented by the angle connection 286 shown bolted to the framework 318. As the belt 202 comes in to the helical portion, it comes in a slope and must cross over the cage 204 and not interfere with it. Thus, the dolly 208 which supports the belt 202 is higher than the cage 204 and the offset connector member 280 bolted at 294 to the dolly 208 as provided. This member 280 which as shown in Figures 16 and 17 comprises the vertical bar between the dolly 208 and the cage 204 is bolted at the top to the dolly and is connected by connection shown generally at 300 at the bottom to the outside cage bars 204a to ride up and down therewith as the dollies 208 travel over the rolling or slop¬ ing helical rail but also are driven therewith about the vertical axis of the system and along the rail. The connection 300 comprises a back¬ ing plate 302 is provided on the side of the cage 204 opposite to the connector member 280, that is, outside of the cage. The plate 302 and member 280 are bolted together through the cage, with the bolt 303 passing through a member 304 which is conducive to sliding. This member 304 might be short piece of pipe that slides smoothly on the cage bar.

This offset arrangement 280 is not needed for the inside cage 206 since the inside cage does not interfere with the belt 220; it never intersects the belt no matter where it is located vertically. The out¬ side cage 204 is essentially, when viewed from the top, a ring formed of the vertical drive bars. To keep this ring concentric with the rest of the system a tracking roller system as shown generally at 305 is provided. This prevents the ring from drifting or being pulled one way or the other. As shown in Figure 16, the cage rolls on a cage roller system 306 at the bottom thereof and is prevented from twist¬ ing or being pulled from side-to-side by top and bottom cage tracking rollers 308, 310 wherein the top roller is positioned outside of the cage and the bottom roller is positioned inside of the cage. Both the top and bottom tracking rollers 308, 310 and the bottom support roller 306 are secured through flanges 312, 314, 316 to the framework 318.

The dollies are preferably not linked or tied together, though it is within the scope of this invention to do so with chain, rope or the like. In one embodiment the outside cage 204 would have an outer diameter of fourteen feet and four inches, the inside cage 206 would have an outer diameter of nine feet and zero inches, and the belt 202 would have a width of thirty inches. There might be fifty some dollies riding on the outside cage.

Thus, for the double-edge stacking system of 200, the outer cage 204 is similar in construction to that of the inner cage 206. A first difference is that the drive bars 204a face radially inward because the belt 202 is inside of the cage 204. Secondly, the outer cage 204 is only of a sufficient height to drive the troiley support system similar to the inner one. The inner cage 206 would still be the primary belt drive extending to the top of the helical path. The outer cage 204 as previously described would also not have an internal hub similar to the hub 360 of the inner cage 206. Rather stationed at var¬ ious locations around the periphery thereof would be provided support and thrust rollers 306, 308, 310 to hold the cage in position. Sprocket segments best shown in Figure 18 around the outer ring cage drive the cage.

Since an offset connector member 280 was needed, the Figure(s) 17 (and 18) embodiment allows the offset member to be one of the sliding members instead of having the dollies 208 through the offset member slide up and down the drive bars 204a of the cage 204 as in Figure 16. The cage was reduced down to the size of the C-channel 330 shown in cross-section in Figures 17 and 18. Thus, instead of the cage, a C-shaped channel was bent around and guide blocks 332 secured to it to receive the offset members 280 sliding up and down through it. Chain teeth, as best shown in Figure 18 at 335, are welded to and inside the C-shaped channel. The channel and thus the guide block and the connecting member are driven by chain 250 engaging the chain teeth 335. Thus, everything in Figure 17 rotates except the right-angled structure 336 on the left, the rails 209 and 348 attached to it, and the flanged structure on the right. In Figure 16 the elevation of the cage bars 204a is constant and the connector members 280 depending from the trolleys 208 slide up and down the cage bars. In Figure 17, in contrast, the guide blocks 332 which go around the C-shaped channel 332, remain at the same level; there are no cage bars (204a). Thus, the connector member 280 changes in ele¬ vation as the dolly 208 rolls around the cam track 209 — it slides through a constant elevation guide block 332. This better stabilizes the tops of the dollies 208 from back and forth movement. This is because the connecting member 280 after it goes through the guide block 332 continues downward and wraps around with member 348 underneath the cam track 209. Two guide rollers 340, 342 maintain the entire assembly in proper vertical orientation.

The large dolly wheel 344 rolls on the angle 346 of track 209. Although the angle 346 changes in elevation, the distance from that angle 346 down to the T-shaped cross section 348 beneath it remains constant. The angle 346 and the "T" 348 thus travel vertically together. The inverted L shaped structure 336 in the left corner structurally supports both the angle 346 and the "T" 348 underneath it. Although it does not move, it is at differing heights depending upon the desired elevation of the angle 346 and the "T" 348 .

The framework 318 is a six-sided top structure of the convey¬ ance system as can best be seen in Figure 15. The outer drive cage 204 does not impact the framework 318 even though in the top plan view of Figure 14 it is pictured at certain locations as being outside and at other locations as being inside of the drive cage. As shown in Figure 15 there is a member 352 on each side of the top positioned at a slight angle that supports the top of the shaft 354 and just below them are a couple of horizontal members 356. These are the members that are illustrated in the plan view of Figure 14 which appear to but do not intersect the outside edge of the cage, but do not as they are at an elevation well above it. The framework 318 and hub structure 224 are tied together with an upper bearing 360 of the cage as shown at the top center of Figure 15.

The wheels 344 of the dollies 208 are flanged to ride over both edges of the helical rail 209 which is depicted as being an angle iron construction 346. It is important to have some type of rolling ele¬ ment for the trolleys or dollies 344 to reduce the friction. An alter¬ native might be the use of a side flexing chain (not shown) having oversized rollers (not shown). More particularly, a double pitched chain wherein every other pin has an oversized roller and side flexing is possible to allow it to run around the tier instead of the trolleys. The outer dollies preferably have the same front and rear axle arrangements as the inner dollies to prevent the bump-up action.

The exit rail system 364 for the double-edge stacker system 200 is preferably the same as that of the single-edge stacker as previously described and as shown for example in Figure 7 at 24. The exit rail 364 is needed on the inside edge since the inside of the belt 202 can¬ not be supported from underneath and as much as the underneath support interferes with the tier beneath it. However, on the outside once the belt 202 leaves the helical portion the belt can be supported from underneath.

The motor controller 366 as shown for example in Figure 14 controls the speed of the system through the motor 218. The belt 202 typically might move at thirty feet per minute but this speed can be varied for example rom eight to two hundred feet per minute. This system 200 is particularly well adapted for conveying and cooling, chilling or freezing meat patties. Some meat patties are not to be frozen but are to be brought down to a temperature very near freez¬ ing. A typical operating temperature, however, for freezing patties is -20 to -40°C.

From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those persons having ordinary skill in the art to which the aforementioned invention pertains. However, it is intended that all such variations not depart¬ ing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A conveying system comprising: a product conveyor belt following an endless path having a helical path portion and a return path portion, said helical path por¬ tion having a bottom tier; a rotatable drive cage disposed generally within said helical path portion and drivingly engaging said conveyor belt along at least a portion of said helical path portion; a continuous support rail positioned generally along said bottom tier, said rail having a helical rail portion generally along said helical path portion and a sloping rail connecting portion; a trolley having at least one trolley wheel riding on said support rail, said trolley carrying at least a portion of said conveyor belt along said bottom tier; and connecting means for connecting said trolley to said drive cage so that said drive cage as it rotates drives said trolley on said trolley wheel and along said helical rail portion.

2. The conveying system of claim 1 further comprising a slack take-up means for taking up the slack of said conveyor belt in said return path portion.

3. The conveying system of claim 1 wherein said helical rail portion extends between two hundred and seventy and three hun¬ dred and fifty degrees around a vertical axis of said drive cage.

4. The conveying system of claim 1 further comprising drive means engaging and driving said conveyor belt along said return path portion and generally adjacent to the exit end of said helical path portion, said drive means being synchronized with the drive of said drive cage.

5. The conveying system of claim 1 wherein said support rail has a flat upper rail surface and said wheel comprises a wheel having flanges which lap over said flat upper rail surface.

6. The conveying system of claim 1 wherein said drive cage comprises a plurality of circumferentially arranged and spaced upright bars, and said connecting means allows said trolley to move vertically relative to said upright bars.

7. The conveying system of claim 6 wherein said connect¬ ing means extends between said bars and slidingly engages an inwardly-facing surface of said bars.

8. The conveying system of claim 6 wherein said connect¬ ing means includes a pair of horizontally-spaced posts extending between adjacent said bars and a bar member attached to said posts and slidingly engaging inwardly-facing surfaces of said bars.

9. The conveying system of claim 1 further comprising a helical rail supporting the outside edge of said conveyor belt along said helical path portion and being open between adjacent tiers thereof and an outer framework supporting said helical rail.

10. The conveying system of claim 1 wherein said trolley is positioned at and supports the interior edge of said conveyor belt at said helical path portion.

11. The conveying system of claim 1 further comprising stacking plates carried by and extending out from said interior edge of said conveyor belt and stacking one on top of another when said con¬ veyor belt is in said helical path portion such that said rail through said trolley supports the interior edge of the entire helical stack of said conveyor belt in said helical path portion.

12. The conveying system of claim 1 wherein said connect¬ ing means maintains said trolley on said support rail as said trolley is driven around said support rail by said drive cage.

13. The conveying system of claim 1 further comprising plate support means or supporting said conveyor belt where said trol¬ ley drops down to said sloping rail connecting portion.

14. The conveying system of claim 1 wherein said trolley has a belt support member having a rearmost end and said at least one wheel comprises front and rear wheels attached to said support mem¬ ber, said rear wheel turning about an axle spaced behind said rearmost end such that, when said trolley turns about said rear wheel axle and drops down on to said sloping rail connecting portion, said support member does not travel upward causing a bump in said conveyor belt thereon.

15. The conveying system of claim 1 further comprising exit rail means for lifting said conveyor belt off said helical path portion to said return path portion.

16. The conveying system of claim 1 wherein said trolley has a belt support member having a f orwardmost end and said at least one wheel comprises front and rear wheels attached to said support member, said front wheel turning about an axle spaced in ront of said forwardmost end such that, when said trolley turns about said front wheel axle and rises up on to said sloping rail connecting portion, said support member does not travel upward causing a bump in said con¬ veyor belt thereon.

17. A conveying system comprising: a product conveyor belt ollowing an endless path having a helical path portion and a return path portion, said helical path por¬ tion having a bottom tier; a rotatable drive cage disposed generally within said helical path portion and drivingly engaging said conveyor belt along at least a portion of said helical path portion, said drive cage comprising a plurality of circumferentially arranged and spaced upright bars; a continuous support rail positioned generally along said bottom tier, said rail having a helical rail portion generally along said helical path portion and a shorter sloping rail connecting portion; a trolley having at least one trolley wheel riding on said support rail, said trolley carrying at least a portion of said conveyor belt along said bottom tier, said trolley having a belt support member having opposite ends and said at least one wheel comprises first and second wheels attached to said support member, one of said wheels turning about an axle spaced outward of one of said ends such that, when said trolley passes over an uppermost end of said sloping rail connecting portion, said support member does not travel upward caus¬ ing a bump in said conveyor belt thereon; and connecting means for connecting said trolley to said drive cage so that said drive cage as it rotates drives said trolley on said trolley wheel and along said helical rail portion, said connecting means allowing said trolley to move vertically relative to said upright bars.

18. A conveying system comprising: a product conveyor belt following an endless path having a helical path portion and a return path portion, said helical path por¬ tion having a bottom tier; a rotatable drive cage disposed generally within said helical path portion and drivingly engaging said conveyor belt along at least a portion of said helical path portion, said drive cage comprising a plurality of circumferentially arranged and spaced upright bars; a continuous support rail positioned generally along said bottom tier, said rail having a helical rail portion generally along said helical path portion and a shorter sloping rail connecting portion; a trolley having at least one trolley wheel riding on said support rail, said trolley carrying at least a portion of said conveyor belt along said bottom tier, said trolley having a belt support member having opposite ends and said at least one wheel comprises first and second wheels attached to said support member, one of said wheels turning about an axle spaced outward of one of said ends such that, when said trolley passes over an uppermost end of said sloping rail connecting portion, said support member does not travel upward caus¬ ing a bump in said conveyor belt thereon; connecting means for connecting said trolley to said drive cage so that said drive cage as it rotates drives said trolley on said trolley wheel and along said helical rail portion, said connecting means allowing said trolley to move vertically relative to said upright bars, and said connecting means extending between said bars and slidingly engaging an inwardly-facing surface of said bars; stacking plates carried by and extending out from said interior edge of said conveyor belt and stacking one on top of another when said conveyor belt is in said helical path portion such that said rail through said trolley supports the interior edge of the entire heli¬ cal stack of said conveyor belt in said helical path portion; and plate support means for supporting said conveyor belt where said trolley drops down to said sloping rail connecting portion.

19. A conveyor system comprising: an endless conveyor belt, a portion of the length of which is caused to follow a helical conveying path including a plural¬ ity of tiers stacked at least partly in a self-supporting manner, one on top of the other; a drive cage located inside the helical conveying path and driving said belt, said cage being drivable in rotation about a gen¬ erally vertical central axis; a plurality of spaced trolleys mounted on a fixed heli¬ cally extending rail to support the lowermost tier of the stack; and driving means for individually driving said trolleys directly by said drive cage.

20. The conveyor system of claim 19 wherein the helically extending rail extends in a helical path around the major part of a single turn of 360 degrees, and over the remaining minor part thereof has a transition section via which in use said trolleys descend from a raised end of said major part to a lower starting point of said major part.

21. The conveyor system of claim 20 wherein above said transition section, said conveyor belt is supported by a fixed transi¬ tion plate, beyond the end of which begins the next tier of the stack above said lowermost tier.

22. The conveyor system of claim 21 wherein said trolleys are slidably attached to vertical guides carried by or forming part of said drive cage.

23. The conveyor system of claim 19 wherein said trolleys are slidably attached to vertical guides carried by or forming part of said drive cage.

24. The conveyor system of claim 19 wherein each said trol¬ ley includes a belt support member and at least one rolling element associated therewith.

25. The conveyor system of claim 24 wherein said at least one rolling element comprises a pair of wheels connected to said belt support member.

26. The conveyor system of claim 19 wherein said drive cage includes vertical guides to which said trolleys are slidably attached.

27. The conveyor system of claim 26 wherein said trolleys include a belt support member and front and rear wheels attached to said support member.

28. The conveyor system of claim 27 wherein said belt sup¬ port member includes a rearmost end and said rear wheel turns about a rear wheel axle spaced behind said rearmost end.

29. A conveyor system comprising: an endless conveyor belt, a portion of the length of which is caused to follow a helical conveying path including a plural¬ ity of tiers stacked one on top of the other; a drive cage located inside the helical conveying path for driving said belt, said cage being drivable in rotation about a gen¬ erally vertical central axis; a plurality of spaced wheeled trolleys separate from said belt mounted on a fixed helically extending rail to support the lower¬ most tier of the stack; and driving means for driving said wheeled trolleys directly by said drive cage.

30. A conveying system comprising: a product conveyor belt following an endless path having a helical path portion and a return path portion, said helical path por¬ tion having a bottom tier; engaging means for drivingly engaging said conveyor belt along at least a portion of said helical path portion; a continuous support rail positioned generally along said bottom tier, said rail having a helical rail portion generally along said helical path portion and an oppositely sloping, rail connecting portion; a trolley system having at least one trolley rolling ele¬ ment riding generally on said support rail, said trolley system carrying at least a portion of said conveyor belt along said bottom tier; and connecting means for connecting said trolley system to said engaging means so that, as said engaging means rotates, said trolley system is driven on its said rolling element along said helical rail portion.

31. The conveying system of claim 30 further comprising drive means engaging and driving said conveyor belt along said return path portion and generally adjacent to the exit end of said helical path portion, said drive means being synchronized with the drive of said engaging means.

32. The conveying system of claim 30 wherein said support rail has a flat upper rail surface and said rolling element has flanges which lap over said flat upper rail surface.

33. The conveying system of claim 30 wherein said engaging means comprises a plurality of circumferentially arranged and spaced upright bars, and said connecting means allows said trolley system to move generally vertically relative to said upright bars.

34. The conveying system of claim 30 wherein said engaging means is disposed generally within said helical path portion.

35. The conveying system of claim 30 wherein said engaging means comprises a rotatable drive cage.

36. The conveying system of claim 35 wherein said rotatable drive cage is disposed within said helical path portion.

37. The conveying system of claim 30 wherein said trolley system includes at least one belt support member and said at least one trolley rolling element comprises a pair of wheels connected to said belt support member.

38. A conveyor belt drive assembly, comprising: a conveyor belt having a row of inner stacker plates on an inner belt edge and a row of outer stacker plates on an outer belt edge, said conveyor belt traveling an endless path having a helical portion and a return portion, said helical portion being associated with an outer helical portion tier; outer-edge wheeled dolly means for carrying thereon at least a portion of said conveyor belt along said outer helical portion tier; and drive means for directly driving said outer-edge wheeled dolly means and thereby at least partially the conveyor belt portion thereon along said outer helical portion tier.

39. The assembly of claim 38 wherein said drive means com¬ prises a drive cage having a plurality of drive bars drivingly engaging said dolly means as said drive cage is rotating about a vertical axis.

40. The assembly of claim 39 wherein said drive means com¬ prises chain driving means for rotatingly driving said drive cage.

41. The assembly of claim 39 wherein said drive means com¬ prises a plurality of connector bars between said dolly means and said drive bars which allow the dolly means to be driven around said heli¬ cal tier portion and on the vertical curves of said vertical tier portion.

42. The assembly of claim 38 wherein said helical portion tier is positioned outside of said drive cage.

43. The assembly of claim 38 wherein said drive means com¬ prises a drive cage engaging said outer-edge wheeled dolly means and mechanized rotating means for rotating said drive cage and thereby said outer-edge wheeled dolly means along the outer helical portion tier.

44. The assembly of claim 43 wherein said drive cage includes a plurality of circumferentially spaced vertical cage bars along which said outer-edge wheeled dolly means slide.

45. The assembly of claim 43 further comprising a frame¬ work assembly supporting said drive cage, and roller means, supported by said framework, and on and against which said roller cage rides when rotated by said rotating means.

46. The assembly of claim 45 wherein said roller means comprises cage tracking rollers and cage bottom support rollers.

47. The assembly of claim 46 wherein said cage tracking rollers comprise, relative to said drive cage, top inside tracking roll¬ ers and bottom outside tracking rollers.

48. The assembly of claim 46 wherein said bottom support rollers includes a pair of spaced roller systems both rotating about vertical axes and with the lower end of said drive cage.

49. The assembly of claim 46 wherein said tracking rollers includes a drive ring assembly.

50. The assembly of claim 49 wherein said drive ring assem¬ bly includes a channel with teeth and guide blocks.

51. The assembly of claim 38 further comprising an inner helical portion tier and an inner-edge wheeled dolly means for carry¬ ing thereon the inner edge of said conveyor belt.

52. The assembly of claim 51 wherein said drive means drives said inner-edge wheeled dolly means.

53. The assembly of claim 52 wherein said drive cage defines an inner drive cage, and said drive means comprises an inner drive cage which drives said inner-edge wheeled dolly means.

54. The assembly of claim 53 wherein said drive means com¬ prises a drive motor and distributing means for distributing power from said drive motor to simultaneously rotatingly driving said inner and outer drive cages.

55. The assembly of claim 54 wherein said distributing means comprises a gear box-sprocket assembly.

56. A conveyor belt drive assembly, comprising: a helical rail tier having vertically sloping portions; a helically-stackable conveyor belt; wheeled trolley means riding on said tier and on said sloping portions for carrying said conveyor belt; downwardly-depending, connector means affixed at an upper portion thereof to said wheeled trolley means and having a lower portion; and driving means for driving said lower portion such that said wheeled trolley means is thereby caused to travel along said tier.

57. The assembly of claim 56 wherein said driving means includes a sleeve in which said connecting member is vertically slidable and drive means for driving said sleeve.

58. The assembly of claim 57 wherein said drive means com¬ prises a channel secured to said sleeve and a teeth-chain sprocket means for driving said channel.

59. The assembly of claim 58 wherein said channel com¬ prises a curved C-shaped channel and said teeth-chain sprocket means comprise chain teeth welded inside said curved C-shaped channel.

60. The assembly of claim 56 further comprising roller means for keeping said connector member aligned with said tier.

61. A conveyor belt conveying system, comprising: path means for defining a continuous support path hav¬ ing an upwardly sloping helical rail portion and a shorter sloping rail connecting portion; a conveyor belt; a trolley riding on said path and carrying a portion of said conveyor belt thereon, said trolley including a belt support mem¬ ber having a rearmost end, a front wheel attached to said belt support member, and a rear wheel attached to said support member, said rear wheel turning about an axle spaced behind said rearmost end such that when said trolley turns about said front wheel axle and rises up on to said sloping rail connecting portion, said support member does not travel upward causing a bump in said conveyor belt thereon.