Product feed system for a compensating stacking machine and method of using same

Abstract

A machine and method is disclosed for stacking product, including but not limited to, cardboard, magazines, newspapers, newspaper supplements, flyers, press signatures, and softcover books. The stacking machine includes an infeed assembly for receiving a product stream or flow. The infeed assembly includes a belt jogger assembly for aligning and distributing product as it enters the machine. A transport assembly delivers product from the infeed assembly to a stacking assembly.

Description

FIELD OF THE INVENTION

The present invention relates generally to the field of automated stacking machines, and, more particularly, to stacking machines that use compression and can use compensation in forming the stacks.

BACKGROUND OF THE INVENTION

For mass production of printed media, stacking machines are used to organize, count, stack, compress and package product such as magazines, newspapers, newspaper supplements, flyers, and press signatures for shipment. These machines typically include a feeder or supply component comprising a conveyor system for receiving product to be stacked. Next, through a combination of conveyors and mechanical apparatus, the products are organized into stacks, which are then compressed for shipment as they exit the machine. For maximum stability of the compressed stacks, compensation is often used in which stack portions are alternately rotated 180° during compression to counteract any tendency or bias to lean in a specific direction.

While existing stacking machines are useful for their intended purposes, they are accompanied with several drawbacks: First, misshapen or misaligned product are prone to jam inside the machines resulting in lost production time and sometimes requiring disassembly of the machine to free the jam. Second, existing machines use plates, rollers or similar devices to move belts in and out to align product, which is ineffective in some applications. Third, when changing product lines, existing machines frequently require adjustments to the conveyor belt assembly to accommodate a new product size. These adjustments can be time consuming and potentially result in more product jams inside the machine if the adjustments are inaccurate. Fourth, the stacking apparatus used by existing machines is often inefficient by requiring a product stack portion or lift to be filled and expelled from the machine before the stacking apparatus is ready to receive more product. Fifth, although compression of the product is a critical factor in minimizing space and maximizing stability in shipping, most existing stacking machines are designed to provide only one or no application of compression to the product, particularly at high speed. Finally, existing stacking machines, due to their location of the product counter, do not consistently give accurate product quantities per lift or stack portion.

Accordingly, there exists a need for an improved compensating stacking machine that reduces jams resulting from entry of misshapen or misaligned product. Furthermore, it is desirable that maximum product alignment be achieved through the use of belt joggers. It is also desirable that the compensating stacking machine accommodate multiple product lines with a minimum of adjustments when switching between lines. Additionally, it is desirable that the stacking machine provide an improved stacking assembly capable of processing more than one lift or stack portion at a time and that each lift, stack portion, or product stack is compressed at least once and preferably more than once. For uniformity in lift size and quantity, it is desirable to attain an accurate count of product before forming the lift.

SUMMARY OF THE INVENTION

Certain objects, advantages and novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention.

To achieve the advantages and novel features, the present invention is generally directed to a machine and method for stacking products, including but not limited to, cardboard, magazines, newspapers, newspaper supplements, flyers, press signatures and softcover books for shipment.

Specifically, the present invention includes an infeed assembly for receiving a product stream or flow. The infeed assembly includes a belt jogger assembly for aligning product as it enters the machine. A transport assembly delivers product from the infeed assembly to a stacking assembly.

The invention can also be viewed as providing a method for stacking product. In this regard, the method can be broadly summarized by the following steps: A product stream is provided and channeled through a belt jogger assembly for alignment and distribution. Once aligned, the product stream is conveyed to a stacker assembly where a plurality of interrupters are used to create gaps in the product flow stream to assist in setting apart a single lift. Product is allowed to accumulate onto a separator until a single lift of product is obtained. The single lift is delivered to a pair of elevators where a first round of compression is applied. After the compression is complete, the lift is delivered to a turntable where a compressor plate applies a second round of compression.

In accordance with another aspect of the present invention, the belt joggers mechanically cooperate with outer belt assemblies such that adjustments to the belt joggers based on product size automatically create corresponding adjustments to the outer belt assemblies ensuring the right combination of belt jogger and outer belt assembly positioning.

In accordance with yet another aspect of the present invention, the stacking assembly includes a plurality of air powered interrupters that create gaps in the product stream to assist in separating the product into a lift or stack portion.

In accordance with still another aspect of the present invention, the stacker includes a laser counter for counting the number of products in each lift or stack portion.

Additional advantages will become apparent from a consideration of the following description and drawings:

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more readily understood from the following detailed description when read in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a compensating stacking machine according to the present invention;

FIG. 2 is an elevation view of the compensating stacking machine of FIG. 1 showing the adjustment capability of the product infeed assembly;

FIG. 3A is a perspective view of the belt jogger assembly used in the infeed assembly of FIG. 2 ;

FIG. 3B is a perspective view of the infeed table belt used in the belt jogger assembly of FIG. 3A ;

FIG. 3C is a perspective view of the belt jogger assembly of FIG. 3A without the infeed table belt of FIG. 3B ;

FIG. 3D is a perspective view of the belt jogger drive pulleys shown in FIGS. 3A and 3C ;

FIG. 4A is a plan view of rotary joggers used to guide product into the stacking assembly portion of the compensating stacking machine of FIG. 1 ;

FIG. 4B is an elevation view of the rotary joggers of FIG. 4 A and their relationship to the stacking assembly;

FIG. 5 is an elevation view of the stacking assembly used in the compensating stacking machine of FIG. 1 ;

FIG. 6A is a plan view of the turntable compression plate upon which product is received as part of the stacking assembly of FIG. 5 ; and

FIG. 6B is an elevation view of the turntable compression plate of FIG. 6 A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof is shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Referring now to FIG. 1 , a perspective view of a compensating stacking machine employing the instant invention is shown. Stacking machine 20 receives an incoming product stream to be stacked through an infeed assembly comprising a belt jogger assembly 22 and trapped belt conveyor 24 a,b . As used herein, product refers most generally to any item having sufficient flexibility and possessing a sufficiently planar geometry to lend itself to stacking. Examples of such items include, but are not limited to, cardboard, magazines, newspapers, newspaper supplements, flyers, press signatures and softcover books.

Stacking machine 20 further comprises a feed table belt assembly 26 for transporting product from the infeed assembly to a stacking assembly. Feed table assembly 26 delivers product to a pair of rotary joggers 28 (one shown) for reception in the stacking belt assembly. A laser counter 32 is located in proximity to the rotary joggers 28 to count product as it is delivered.

The stacking assembly portion of stacking machine 20 includes a top interrupter 34 that is used to create gaps in the product stream that enters the stacking assembly. Top interrupter 34 is designed to retract from the flow of product thereby allowing product to accumulate on lift separator 36 . Product is allowed to accumulate on the platform provided by lift separator 36 until a single “lift” quantity is reached. At that point, lift separator 36 will retract thereby delivering the product lift to either left elevator 38 a or right elevator 38 b . The left and right elevators 38 a,b are designed to descend within the stacking assembly to meet turntable compressor plate 42 , which ascends to receive the lift. Turntable compressor plate 42 is received in a depression in turntable 44 such that turntable compressor plate 42 is flush with turntable 44 . A delivery belt 45 is positioned proximal to turntable 44 where product is expelled from stacking machine 20 .

Disposed on the undercarriage of the stacking machine 20 are a plurality of wheels 47 , or the like, to provide for mobility of the stacking machine 20 . Also disposed on the stacking machine 20 is a position locking means 49 as is commonly known in other arts.

With this general understanding of the present invention, the architecture and operation of the various sub-assemblies of stacking machine 20 will be described hereafter.

Referring now to FIG. 2 , the incoming product enters stacking machine 20 via belt jogger assembly 22 . The entire infeed assembly of belt jogger assembly 22 and trapped belt conveyor 24 a,b is designed to rotate about pivot 46 anchored in the housing of stacking machine 20 through operation of pneumatic cylinder 48 , which is attached to the base of stacking machine 20 , to allow the infeed assembly to accommodate varying product supply conveyor heights. Pneumatic cylinder 48 is connected to belt jogger assembly 22 via a slotted coupling 52 (see FIG. 1 ), which further enhances the height adjustment capability for the infeed assembly.

In addition to matching the height of the belt jogger assembly 22 to the infeed conveyor, pneumatic cylinder 48 can be used to reject misshapen or misaligned products before they proceed into the internals of stacking machine 20 where they could cause a jam. For example, pneumatic cylinder 48 can be activated by pressing a button on a touchscreen display (not shown) or by pressing a button (not shown) on the side of stacking machine 20 to swing belt jogger assembly 22 and trapped belt conveyor 24 a,b upward to cause product to fall off of the end of the supply conveyor that is delivering product to the stacking machine 20 . A basket or collection bin can be positioned underneath belt jogger assembly 22 and the end of the product supply conveyor to collect the rejected product. Advantageously, pivot 46 is positioned near the location where trapped belt conveyor 24 a,b joins the body of stacking machine 20 , thus allowing for a wide degree of adjustment due to the large radius.

As discussed in the foregoing, stacking machine 20 receives product to be stacked through belt jogger assembly 22 . Referring now to FIG. 3A , belt jogger assembly 22 includes two uniquely designed belt joggers 54 a,b . Belt joggers 54 a,b are positioned on both sides of belt jogger assembly 22 to ensure that product is oriented correctly as it proceeds through stacking machine 20 . Specifically, belt joggers 54 a,b use drive pulleys 56 a,b having a plurality of flat sides formed thereon to provide a pulsating effect in the speed of belts 58 a,b as product passes by. Typically, drive pulleys 56 a,b include three or four flat sides to achieve the desired effect. Product passes between belt joggers 54 a,b on infeed table belt 64 , shown best in FIG. 3B , and outer infeed belts 66 a,b . It should be noted that infeed table belt 64 is shown in FIGS. 3A and 3B as a separate belt from lower belt section 24 b of trapped belt conveyor 24 a,b for illustrative purposes only. When belt jogger assembly 22 and trapped belt conveyor 24 a,b are assembled to one another to form the infeed assembly, a single, endless belt is used to implement both infeed table belt 64 and lower belt section 24 b.

Infeed table belt 64 , outer infeed belts 66 a,b , and belt joggers 54 a,b are driven by driveshaft 65 . Belts 58 a , b are endless and cycle on drive pulleys 56 a,b and idler pulleys 62 a,b . Product is more effectively aligned on infeed table belt 64 through both the pushing process of belt joggers 54 a,b and pulses from the varying speed of belts 58 a,b . Moreover, the pulsating effect creates a more uniform distribution of product in the product stream. That is, gaps in the product stream are closed while concentrations of product in the stream are spaced apart.

FIG. 3D illustrates in detail the drive pulley 56 a,b . Drive pulley 56 , having a plurality of flat sides formed thereon as shown, drives jogger belt 58 (corresponding to belts 58 a,b of FIG. 3 A). One skilled in the art will appreciate that drive pulley 56 will have a plurality of differing radii. Drive pulley 56 will have a plurality of maximum radii (R max ), each at the junction of each flat side. Also, drive pulley 56 will have a plurality of minimum radii (R min ), each at the center of each flat side. In between R max and R min the radius of drive pulley 56 will be constantly changing as shown by the plurality of radii 57 on FIG. 3 D. As the jogger belt 58 is driven by drive pulley 56 , a vibratory effect will be created in jogger belt 58 from the continual changing radii 57 , which increases as the drive pulley radius contact point with jogger belt 58 changes from R min to R max and then decreases as the radii 57 changes from R max back to R min . Furthermore, since the speed of movement of jogger belt 58 is directly proportional to the radius of the drive pulley 56 , the speed of movement of jogger belt 58 will pulsate between a faster speed associated with R max and a slower speed associated with R min . Thus, drive pulley 56 effectively vibrates belt 58 and pulsates the speed of the movement of belt 58 .

Referring now to FIG. 3C , an important feature of belt jogger assembly 22 is that belt joggers 54 a,b can be adjusted to conform to the size of the product being processed. Advantageously, adjustments to belt joggers 54 a,b are simultaneously transferred to outer infeed belts 66 a,b via a mechanical relationship. Specifically, belt joggers 54 a,b are each threadably mounted on acme screws 68 a,b that adjust the horizontal position of belt joggers 54 a,b relative to infeed table belt 64 (see FIG. 3 A). Outer infeed belts 66 a,b , which are preferably smaller than infeed table belt 64 , move in concert with belt joggers 54 a,b through roller chains (not shown) that are controlled by acme screws 68 a,b . Outer infeed belts 66 a,b are arranged in a slightly depressed position with respect to infeed table belt 64 . Consequently, as belt joggers 54 a,b move in towards infeed table belt 64 , outer infeed belts 66 a,b will slide underneath infeed table belt 64 leaving infeed table belt 64 as the sole means of transport for narrow products. The linkage of belt joggers 54 a,b to outer infeed belts 66 a,b results in faster and more accurate adjustments when switching stacking machine 20 over to accommodate a new product line. Heretofore, a technician would have to adjust both belt joggers 54 a,b and outer infeed belts 66 a,b separately resulting in frequent jams and alignment problems until a proper configuration could be obtained through an iterative process. It is envisioned that belt joggers 54 a,b as described herein could be used in alternative material handling machinery where product alignment is desired. For example, the belt jogger assembly 22 and/or the individual belt joggers 54 a,b could be used in conveyor systems to maintain the alignment and proper distribution of a product stream. The belt jogger assembly 22 and/or belt joggers 54 a,b may also be used ahead of a trimmer machine as proper alignment is critical if product is to be successfully trimmed. Finally, the belt jogger assembly 22 and/or belt joggers 54 a,b can be used at the infeed of other types of stacking machines.

Returning to FIG. 1 , once product has passed through belt jogger assembly 22 , it will be conveyed upward through trapped belt conveyor 24 a,b . Trapped belt conveyor 24 a,b is comprised of two endless belt sections: upper belt section 24 a and lower belt section 24 b . Each section comprises a series of endless belts carried by idler pulleys positioned adjacent one another. The two endless belt sections, 24 a and 24 b , are positioned opposite one another such that the surface of each belt in each section contacts a corresponding belt in the opposite section over a portion of its circumference to form a contact region 24 c . Product is effectively “trapped” in contact region 24 c and transported through stacking machine 20 . In addition to providing a transport function, trapped belt conveyor 24 a,b also flattens the product between the belts in contact region 24 c . While a series of belts are used in the preferred embodiment, it is envisioned that alternative embodiments could use a single broad belt for each of the belt sections.

Trapped belt conveyor 24 a,b delivers the product to feed table belt assembly 26 , which continues the progression of product towards the stacking assembly. Upper belt section 24 a extends over the top of feed table belt assembly 26 . As a result, upper belt section 24 a and feed table belt assembly 26 operate in the same manner as trapped belt conveyor 24 a,b with product being confined and transported between endless belts cycling on idler pulleys. Thus, upper belt section 24 a and feed table belt assembly 26 form a second trapped belt conveyor system.

Referring now to FIGS. 4A , 4 B and 1 , a pair of rotary joggers 28 a,b are shown to provide final side-to-side alignment adjustments and drive the product towards a stop for proper front-to-back alignment. A laser counter 32 is advantageously located in the housing or box containing the rotary joggers to ensure an accurate count of the product. The location of laser counter 32 at a position after the product has already been evaluated for proper sizing, aligned, and uniformly distributed through the belt jogger assembly 22 ensures more accurate counts of product as the likelihood of product jams at this stage in the stacking process is substantially minimized. This stands in contrast to the practice in prior art stacking machines of counting product as it enters the machine or at a “stream stop area” resulting in inaccurate counts when product jams occur or when product is located too close to one another for the counter to properly distinguish one item from the next.

At this stage the product is ready to enter the stacking assembly portion of stacking machine 20 . Shown best in FIGS. 5 and 4B , the stacking assembly comprises a top interrupter 34 , a lift separator 36 , and left and right elevators 38 a and 38 b . Product will begin to descend between supports 74 and collect on top interrupter 34 until a desired count is reached on laser counter 32 or, if a stack height sensor is used, until the desired height is reached. Once this threshold is reached, top interrupter 34 retracts thereby dropping the partial lift onto lift separator 36 where product continues to accumulate until the desired count is reached on laser counter 32 or a stack height sensor is tripped. Top interrupter 34 and lift separator 36 should have sufficient strength to support the weight of a single lift or stack portion. At that point, top interrupter 34 will shoot underneath the last of this lift or stack portion to set apart this lift from the stream of product coming from feed table belt assembly 26 and upper belt section 24 a . The motion of top interrupter 34 is indicated by arrows in FIGS. 4B and 5 .

In other words, top interrupter 34 is used to create gaps in the product flow corresponding to the chosen lift size. In the preferred embodiment, top interrupter 34 is comprised of multiple hollow prongs or fingers made from a suitable rigid material such as stainless steel, aluminum, or a special plastic such as nylatron, spaced a suitable distance from one another and powered by an air compressor that propels a burst of air through holes in the prongs to define a clean separation between the product. By using compressed air, the prongs easily insert into the product stream to form a gap in the product stream without slowing down the overall flow, which allows the machine to run at higher speeds than would be possible if alternative means were used to segregate the individual lifts. Furthermore, the use of compressed air minimizes the tendency for interrupter tab prongs to catch on the product, which frequently causes damage to the product or jams in the machine. While the preferred embodiment uses one top interrupter 34 , the number used is dependent on the machine speed desired. Thus, alternative embodiments may use a single top interrupter 34 for low speed applications or multiple interrupters when running at high speeds. The top interrupter 34 described herein could also be used in alternative material handling machinery where it is desired to create gaps in product flow.

Next, lift separator 36 opens up to allow the lift to descend further downward between supports 74 to either left elevator 38 a or right elevator 38 b . Lift separator 36 closes again after the entire lift has been received by one of the elevators 38 a,b . As shown in FIGS. 4B and 5 , left elevator 38 a is in position to receive a lift. Once a lift is in place, left elevator 38 a will descend with the lift and right elevator 38 b will move into the position formerly occupied by left elevator 38 a to receive the next lift. After reaching its lowest position, left elevator 38 a will then move upward to individually compress the lift it holds between itself and the lower surface of right elevator 38 b.

Referring now to FIGS. 5 , 6 A, and 6 B, after compressing its lift against the lower surface of right elevator 38 b , left elevator 38 a drops back down to its lowest position and opens up to deposit the lift onto turntable compressor plate 42 , which has ascended to receive the lift via operation of compressor plate pneumatic cylinders 75 . Turntable compression plate 42 will then descend with the lift until the plate is flush with turntable 44 . To apply a second, more powerful compression, turntable top compressor bars 76 extend from guidebars 78 to provide a brace against which turntable compressor plate 42 rises to compress the lift. Turntable 44 is rotatable so that each lift can be rotated 180° with respect to the previous lift before it is compressed to provide optional compensation to the stack. Thus, every lift will be compressed at least once and preferably twice: once individually between elevator pairs 38 a and 38 b , and second, between turntable compressor plate 42 and top compressor bars 76 . Moreover, if a stack is comprised of more than one lift, then every lift except the last one to complete the stack will be compressed multiple times on turntable compressor plate 42 . When stacking machine 20 is running at extremely high speeds, it is sometimes desirable to forego the second compression between turntable compressor plate 42 and top compressor bars 76 . Nevertheless, each lift will receive at least one application of compression between elevator pairs 38 a and 38 b.

Once the desired stack height is reached, pusher rod pneumatic cylinders 81 cause pusher rod 82 to emerge from a slot in turntable compressor plate 42 to engage the side of the stack and push the stack out of stacking machine 20 onto delivery belt 45 . Stacking machine 20 can be configured to expel stacks on either the left or right sides. In the preferred embodiment, sensors are used on the sides of stacking machine 20 to detect if a previously expelled stack has not been cleared and direct the machine to expel the current stack to the other side.

In addition to providing multiple compression to each lift, the stacking assembly described herein can operate at much higher speeds than have heretofore been possible primarily through the use of an interrupter, separator, and multiple elevators that allow the machine to operate on more than one lift or stack portion at a time. Existing stacking machines generally require one lift to be expelled before operating on the next lift. While a single interrupter and dual elevators are disclosed herein as the preferred embodiment, it is envisioned that the number of interrupters and elevators could be increased to operate the machine at even higher speeds and efficiency levels.

It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are merely possible examples of implementations, merely set forth for a clear understanding of the principles of the present invention. Many variations and modifications may be made to the abovedescribed embodiment(s) of the present invention without departing substantially from the spirit and principles of the present invention. All such modifications and variations are intended to be included herein within the scope of this disclosure of the present invention and be protected by the following claims.

Claims

1. A mechanism for transporting products in a product transport system, comprising:a table belt having a left side and a right side, said table belt disposed substantially horizontally and adapted to convey a plurality of products; a pair of jogger assemblies, each assembly comprising: a plurality of drive pulleys; a jogger belt disposed in a substantially vertical orientation in each one of said assemblies, said jogger belt having an inner side, an outer side, and a bottom edge, and wherein each one of said jogger belts is driven by at least one of said plurality of drive pulleys; an inner belt disposed in a substantially horizontal orientation in each one of said assemblies, said inner belt having an outside edge and an inside edge, wherein each one of said inner belts is adjacent and substantially perpendicular to the inner side and bottom edge of each one of said jogger belts, and wherein said inner belt is configured to fit within said table belt; and means for mounting said pair of jogger assemblies such that said jogger belt and said inner belt pairs oppose each other, and such that said belt jogger and said inner belt pairs can be moved in concert relative to said table belt, wherein said table belt is disposed between said pair of jogger assemblies such that said mounting means may be adjusted to change the distance between said jogger belts to accommodate varying dimensions of said plurality of products, and such that said jogger assemblies convey said plurality of products in a vibratory manner causing said continuous flow of said products to more uniformly align on said table belt.

2. The mechanism of claim 1, wherein said drive pulleys have a plurality of drive surfaces formed thereon.

3. The mechanism of claim 2, wherein each one of said plurality of drive surfaces are substantially planar.

4. A mechanism for transporting products in a product transport system, comprising:a table belt having a left side and a right side, said table belt disposed substantially horizontally and adapted to convey a plurality of products; a pair of jogger assemblies, each assembly comprising: a plurality of drive pulleys; a jogger belt disposed in a substantially vertical orientation in each one of said assemblies, said jogger belt having an inner side, an outer side, and a bottom edge, and wherein each one of said jogger belts is driven by at least one of said plurality of drive pulleys; and an inner belt disposed in a substantially horizontal orientation in each one of said assemblies, said inner belt having an outside edge and an inside edge, wherein each one of said inner belts is adjacent and substantially perpendicular to the inner side and bottom edge of each one of said jogger belts, and wherein said inner belt is configured to fit within said table belt; wherein said table belt is disposed between said pair of jogger assemblies such that position of said jogger belt assemblies may be adjusted to change the distance between said jogger belts to accommodate varying dimensions of said plurality of products, and such that said jogger assemblies convey said plurality of products in a vibratory manner causing a continuous flow of said products to more uniformly align on said table belt.

5. The system of claim 4, further comprising at least one screw coupled to said jogger belts and said inner belts such that said jogger belt and said inner belt pairs oppose each other, and such that said jogger belt and said inner belt pairs can be moved in concert relative to said table belt.

6. A jogger assembly comprising:a jogger belt disposed in a substantially vertical orientation in said jogger assembly, said jogger belt having an inner side, an outer side, and a bottom edge, and wherein said jogger belt is driven by at least one drive pulley; and an inner belt disposed in a substantially horizontal orientation in said jogger assembly, said inner belt having an outside edge and an inside edge, wherein said inner belts is adjacent and substantially perpendicular to said inner side and said bottom edge of said jogger belt, wherein said inner belt is configured to fit within a table belt such that a portion of said inner belt overlaps with a portion of said table belt, and such that said jogger assembly can be moved while maintaining said overlap.

7. The jogger assembly of claim 6, further comprisinga pulley having a plurality of flat sides formed thereon and disposed within said jogger belt and in contact with said inner side of said jogger belt such that said jogger belt pulsates.

8. The jogger assembly of claim 6, further comprising at least one screw configured to couple to said jogger belt and said inner belt such that when said screw is turned, said jogger belt and said inner belt move in unison so as to maintain their relative position with respect to each other.

9. A jogger assembly comprising:a jogger belt disposed in a substantially vertical orientation in said jogger assembly, said jogger belt having an inner side, an outer side, and a bottom edge, and wherein said jogger belt is driven by at least one drive pulley; an inner belt disposed in a substantially horizontal orientation in said jogger assembly, said inner belt having an outside edge and an inside edge, wherein said inner belts is adjacent and substantially perpendicular to said inner side and said bottom edge of said jogger belt; and at least one screw configured to couple to said jogger belt and said inner belt such that when said screw is turned, said jogger belt and said inner belt move in unison so as to maintain their relative position with respect to each other.