TROLLEY WITH TRACTOR DRIVE FOR USE IN CURVED ENCLOSED TRACKS AND SYSTEM INCLUDING THE SAME
An enclosed track system comprising an enclosed track having at least one curve and a trolley for negotiating the curve. The trolley includes an externally located drive section and a rolling section having first and second roller portions located within the track. The first roller portion includes rollers for rolling on flange portions of the track. The second roller portion includes a driven wheel and a pair of support rollers. The driven wheel rolls on an inner surface of the top of the track. The pair of support rollers roll on flange portions of the track and are mounting on respective rods for pivoting action about vertical axes. The drive section includes a motor, a drive sprocket and associated chain for positively driving the driven wheel. The drive section also includes an articulated joint coupling the first and second roller portions together.
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Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot Applicable
INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISKNot Applicable
BACKGROUND OF THE INVENTION1. Field of Invention
This invention relates generally to overhead conveyor systems and more particularly to systems making use of an enclosed track in which a trolley is arranged to roll to support something from the trolley.
2. Description of Related Art
Enclosed track conveyor systems are commonly used to support and carry items from a wheeled trolley located within the interior of an enclosed track. As is known enclosed tracks are hollow members having a top-wall, a pair of sidewalls projecting downward from the top wall and a pair of marginal flanges extending horizontally from respective ones of the sidewalls. The flanges are spaced from each other to form a slot therebetween. The trolley is located within the interior of the track, with its wheels or rollers disposed on the interior (upper) surface of the flanges.
Examples of enclosed track systems including internally located trolleys for rolling down the interior of the track are found in U.S. Pat. No. 3,589,503 (Leach), U.S. Pat. No. 3 627,595 (Leach) and U.S. Pat. No. 6,450,326 (Hoffinan et al.). The trolleys of the foregoing patents are arranged so that they can negotiate curves in the track.
In some prior art systems, the movement or rolling of a trolley down the interior of an enclosed track is accomplished by using a tractor drive that is mounted on the trolley, but located outside of the track. Such tractor drives make use of a drive wheel, which extends through the slot in the track to frictionally engage the inner surface of the top wall of the track. The drive wheel is rotated by a motor mounted on the externally located tractor. This arrangement requires that the drive wheel be of a relatively large diameter. As a result such tractors are not suitable for use in systems wherein the enclosed track includes a relatively small radius curve, since the drive wheel would engage or bind in the slot. While some enclosed track systems make use of tractors having drive wheels that engage and ride on the bottom of the track, i.e., the inner surface of one or more of the flanges, such systems are not practical due to splices used on the track, which results in an uneven drive surface, and make it difficult to keep a constant pressure on the drive wheel.
In U.S. Pat. No. 6,718,885, which is assigned to the same assignee as this invention and whose disclosure is incorporated by reference herein, there is disclosed an enclosed track system that makes use of a drive system facilitating the driving of a trolley through a curve in an enclosed track. To that end, the system of that patent includes an enclosed track system comprising an enclosed track having at least one curved portion and a trolley. The track includes a slot extending along its length. The trolley includes a rolling section having first and second roller portions and an externally located drive section. The first and second roller portions are located within the track and spaced from each other. The second roller portion includes a pair of guide rollers disposed within the slot in the track and a passive or floating driven wheel located within the track. The driven wheel is arranged to be driven by frictional engagement of a driving wheel and is arranged to roll on an inner surface of the track to propel the trolley along the track. To the end the drive section includes a motor to cause the drive wheel to rotate, whereupon it causes the driven wheel to rotate so that the trolley rolls along the track. The drive section has an articulated joint coupling the first and second roller portions to each other, with the articulated joint enabling the first and second roller portions to pivot longitudinally with respect to each other so that the trolley can negotiate curves in the track. The articulated joint is in the form of a dual-hinged, articulated tow-arm assembly. That assembly basically comprises an elongated tow-arm member having a pair of brackets at its opposite ends. One bracket is secured via a hinged connection to a portion of the frame supporting the motor at the second roller portion, while the other bracket is secured via a hinged connection and an associated clevis to a portion of the first roller portion. The pivot point at the second roller portion is located forward of the longitudinal position of the guide rollers.
While the drive system of the '885 patent is suitable for its intended purposes, it leaves something to be desired from two standpoints. In particular, one is potential slippage of the driven wheel, since it is a floating member driven by frictional engagement from the driving wheel. The other is possible side loading torque resulting from the construction of the articulated joint coupling, and in particular the fact that the pivot axis for the second roller portion is located forwardly of the guide rollers and the point at which the driven roller engages the inner surface of the track. Such a side load torque could result in accelerated wear of the guide rollers.
BRIEF SUMMARY OF THE INVENTIONThis invention relates to a trolley for use with an enclosed track having at least one curved portion, the enclosed track being an elongated hollow member having a top wall portion, a pair of side wall portions and a pair of flanged portions, the flanged portions being spaced from each other to define a slot therebetween extending longitudinally along the track. The trolley comprises a rolling section and a drive section, with the rolling section having first and second roller portions. The first roller portion is located within the track and comprises at least one support roller arranged to roll on at least one of the flange portions of the track. The second roller portion comprises a driven wheel, a pair of support rollers and a pair of guide rollers mounted on respective vertically extending rods. Each of the guide rollers is located within the slot of the track, with the guide rollers being positioned immediately fore and aft of the position of the driven wheel. The pair of support rollers comprises an upstream support roller and a downstream support roller. The upstream support roller is located adjacent one side of the drive wheel and is mounted on the drive section for pivoting action about an upstream vertical axis. The downstream support roller is located adjacent a diametrically opposed side of the driven wheel and mounted on the drive section for pivoting action about a downstream vertical axis, whereupon the upstream and downstream support rollers are enabled to roll along at least one of the flange portions of the track while said driven wheel rolls along the top wall portion of the track in the center thereof. The drive section is located outside of the track.
In one preferred aspect of this invention the drive section includes a driving sprocket and an associated driving loop, e.g., a chain. The driving sprocket is arranged for positively engaging the driving loop. The driving loop is arranged for positively engaging the driven wheel to cause the driven wheel to rotate about a horizontal axis so that it rolls on the inner surface of the track to propel the trolley along the track.
In another preferred aspect of this invention the first roller portion of the trolley is coupled to the second roller portion by an articulated joint. The articulated joint comprises an elongated member having a first end portion and a second end portion. The first end portion is pivotably coupled to the first roller portion at a first vertically extending axis. The second end portion is pivotably coupled to the second roller portion at a second vertically extending axis. The second vertically extending axis is located approximately midway between the vertically extending rods for the guide rollers.
The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein:
In
Turning now to
The track 22 is arranged to support at least one trolley 24 to enable the trolley to be driven, i.e., moved, along the track to any desired longitudinal position. The trolley 24 may be used to support or hold some other device or member from it. For example, the trolley 24 can be used to support a lifting device (not shown), such as a winch or hoist or one end of a bridge member to form a bridge crane.
Turning now to
The roller section 28 serves as the second or “rear” roller section of the trolley 24 and also includes two pairs of wheels or rollers located within the interior of the track 22. One pair of rollers is designated by the reference numbers 28A and 28B, while the other pair is designated by the reference numbers 28C and 28D. The rollers 28A-28D are of similar construction to the rollers 26A-26D, but are smaller in diameter, for reasons to become apparent later. The rollers 28A and 28B are mounted on an axle 54 and the roller pair 26C and 26D are mounted on an axle 56. The axle 54 is mounted on a roller support body 58 (
Seated between the pairs of rollers 28A, 28B, and 28C, 28D is a “driven” wheel assembly 62, which serves as the assembly for driving the trolley 24. In particular, as best seen in
Since the sprocket 62C is fixedly secured between the wheels 62A and 62B, rotation of the sprocket 62C causes concomitant rotation of the wheels 62A and 62B. The driven wheel assembly 62 is driven by a drive chain 63 and drive sprocket 64. The sprocket 62C is arranged to be driven, i.e., rotated, by the drive chain 63 under the impetus of the drive sprocket 64. The drive sprocket 64 is located beneath the driven wheel assembly 62 and is also located between the pairs of rollers 28A, 28B and 28C, 28D. The drive chain 63 interlinks the sprocket 62C of the driven wheel assembly 62 and the drive sprocket 64. As best seen in
As best seen in
In order to ensure that the portions of the tractor drive that extend through the slot 46 in the track 22 into its interior, e.g., the driven wheel support body 140 (
The tractor drive trolley 24 basically comprises of a frame 74 (
The pair of flanged bearings 90 which form a portion of the drive wheel assembly 82 are mounted on the upper portion 86 of the frame 74 and serve to journal respective portions of the axle of the drive sprocket 64. As best seen in
The rotation of the output shaft 100 of the speed reducer causes the concomitant rotation of the sprocket 98, which is coupled via the drive chain 96 to the sprocket 92 and to the axle 94 of the drive sprocket 64 to cause it to rotate at the desired speed. It should be appreciated by those skilled in the art that the number of teeth on the two sprockets could be selected to provide a different rotational speed reduction, if desired. Moreover, the motor's speed and the amount of reduction of it by the speed reducer (or by the sprockets) is a matter of choice by the designer of the system.
In order to protect the drive chain and sprockets of the transmission assembly 80, a hollow housing or cover 102 is provided on the frame 74 and extends over the sprockets and the chain. The cover 102 is held in place on the frame 74 via plural screws and lock washers 103.
As mentioned earlier it is the frictional engagement and rotation of the driven wheel 62 on the inner surface of the top wall 32 of the track, which effects the movement of the trolley 24 along the track. In order to ensure that the driven wheel makes good frictional engagement with the interior surface of the top wall 32 of the track 22 to effectively and efficiently move the trolley along the track without slippage, the heretofore spring biasing assembly 84 is provided. That assembly is mounted on the pivot plate 108. The pivot plate 108 is mounted on a vertically extending bolt 112 secured to the middle portion of the frame 74 and basically comprises the heretofore mentioned rod now designated by the reference number 104 (
As should be appreciated by those skilled in the art, by tightening the nuts 110 on the rod 104, the spring 106 is compressed. The natural bias of the spring 106 tends to oppose this compression to thereby pull downward on the rod 104. This downward pulling of the rod 104 pulls the roller mounting body 60 and the rollers 28C and 28D mounted thereon downward. Since the rollers 28C and 28D are in engagement with the inner surfaces of the track's flanges 42 and 44, this downward pull is resisted by the flanges and is translated into an upwardly directed force on the frame 74. Accordingly, an upward force is applied through the driven wheel support body 140 to the driven wheel 62 to force it into good frictional engagement with the inner surface of the top wall 32 of the track 22. Thus, when the driven wheel 62 is driven by rotation of the drive sprocket 64, the driven wheel 62 will roll on the inner surface of the top wall 32 of the track without slippage. This results in the movement of the trolley 24 down the track at a desired speed, e.g., 50 feet per minute using the exemplary rotational speeds of the shafts as discussed above.
In order to ensure that the two roller sections 26 and 28 can readily negotiate curves in the track 22, those roller sections are coupled together by a hinged, articulated tow-arm assembly 30. To that end, as best seen in
The tow-arm member 114 is a weldment having a vertical plate-like member 117 and a horizontal elongated yoke-like or U-shaped, plate member. As best seen in
As best seen in
As best seen in
As best seen in
As should be appreciated from the foregoing, the systems of the subject invention, and in particular their trolleys, are particularly well suited for use in any enclosed track system, even those having a relatively tight or small radius of curvature curves. The trolley 24 can be constructed in various ways and need not include all of the rollers shown and described heretofore. Moreover, other arrangements than that specifically described above can be used to effect the driving or movement of the trolley along the track by means of some motor located outside the track. Further still, this system is not limited to use with powered trolleys. Thus, the trolleys of this invention can be passive ones that are pulled along the track by hand or by some other mechanism located below the track.
While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
Claims
1. A trolley for use with an enclosed track having at least one curved portion, the enclosed track being an elongated hollow member having a top wall portion, a pair of side wall portions and a pair of flanged portions, the flanged portions being spaced from each other to define a slot there between extending longitudinally along the track, said trolley comprising a rolling section and a drive section, said rolling section comprising first and second roller portions, said first roller portion being located within the track and comprising at least one support roller arranged to roll on at least one of the flange portions of the track, said second roller portion comprising a driven wheel and a pair of support rollers, said drive section being located outside of the track and including a driving sprocket and an associated driving loop, said driving sprocket being arranged for positively engaging said driving loop, said driving loop being arranged for positively engaging said driven wheel to cause said driven wheel to rotate about a horizontal axis, said pair of support rollers comprising an upstream support roller and a downstream support roller, said upstream support roller being located adjacent one side of said drive wheel and mounted on said drive section for pivoting action about an upstream vertical axis, said downstream support roller being located adjacent a diametrically opposed side of said driven wheel and mounted on said drive section for pivoting action about a downstream vertical axis, whereupon said upstream and downstream support rollers are enabled to roll along at least one of the flange portions of the track while said driven wheel rolls along the top wall portion of the track in the center thereof.
2. The trolley of claim 1 wherein said driving loop comprises a chain.
3. The trolley of claim 1 additionally comprising at least one spring for biasing said driven wheel into engagement with the top wall of the track.
4. The trolley of claim 1 additionally comprising a pair of guide rollers mounted on respective vertically extending rods connected to said second roller portion, each of said guide rollers being and located within the slot in the track, with said guide rollers being positioned immediately fore and aft of the position of said driven wheel.
5. The trolley of claim 4 wherein said first roller portion is coupled to said second roller portion by an articulated joint, said articulated joint comprising an elongated member, said elongated member having a first end portion and a second end portion, said first end portion being pivotably coupled to said first roller portion at a first vertically extending axis, said second end portion being pivotably coupled to said second roller portion at a second vertically extending axis, said second vertically extending axis being located approximately midway between said vertically extending rods of said guide rollers.
6. The trolley of claim 5 wherein said articulated joint additionally comprises a tow-arm swing plate, and wherein said elongated member is comprises a yoke like member having a pair of arms, each of which includes a respective end fixedly secured to said tow-arm swing plate, said tow-arm swing plate being mounted for pivoting about said second vertically extending axis.
7. A trolley for use with an enclosed track having at least one curved portion, the enclosed track being an elongated hollow member having a top wall portion, a pair of side wall portions and a pair of flanged portions, the flanged portions being spaced from each other to define a slot therebetween extending longitudinally along the track, said trolley comprising a rolling section and a drive section, said rolling section comprising first and second roller portions, said first roller portion being located within the track and comprising at least one support roller arranged to roll on at least one of the flange portions of the track, said second roller portion comprising a driven wheel and a pair of support rollers, said first and second roller portions being coupled together by an articulating joint, said second roller portion comprising a pair of guide rollers mounted on respective vertically extending rods, each of said guide rollers being and located within said slot, with said guide rollers being positioned immediately fore and aft of the position of said driven wheel, said drive section being located outside of the track said driving section being arranged for driving said driven wheel to cause said driven wheel to rotate about a horizontal axis, said pair of support rollers comprising an upstream support roller and a downstream support roller, said upstream support roller being located adjacent one side of said drive wheel and mounted on said drive section for pivoting action about an upstream vertical axis, said downstream support roller being located adjacent a diametrically opposed side of said driven wheel and mounted on said drive section for pivoting action about a downstream vertical axis, whereupon said upstream and downstream support rollers are enabled to roll along at least one of the flange portions of the track while said driven wheel rolls along the top wall portion of the track in the center thereof, said articulated joint comprising an elongated member, said elongated member having a first end portion and a second end portion, said first end portion being pivotably coupled to said first roller portion at a first vertically extending axis, said second end portion being pivotably coupled to said second roller portion at a second vertically extending axis, said second vertically extending axis being located approximately midway between said vertically extending rods of said guide rollers.
8. The trolley of claim 7 wherein said articulated joint additionally comprises a tow-arm swing plate, and wherein said elongated member is comprises a yoke like member having a pair of arms, each of which includes a respective end fixedly secured to said tow-arm swing plate, said tow-arm swing plate being mounted for pivoting about said second vertically extending axis.
Type: Application
Filed: Dec 22, 2006
Publication Date: Jun 26, 2008
Applicant: TRANSOL CORPORATION (Morgantown, PA)
Inventors: Timothy Joseph Bambrick (Mohnton, PA), Arnold Timothy Galpin (Morgantown, PA), Jason Rodney Garman (Gordonville, PA), Brian Lee Fleck (Glenmoore, PA), Michael Richard Hanna (West Grove, PA), David A. Pisotti (Mohnton, PA)
Application Number: 11/615,388