Patent Publication Number: US-2010108474-A1

Title: Conveyor system

Description:
This application is continuation in part of U.S. application Ser. No. 12/349,443 filed on Jan. 6, 2009, which is a continuation of and claims priority to U.S. provisional application 61/081,117 filed on Jul. 16, 2008, which are both hereby incorporated by reference for all that is disclosed therein. 
    
    
     BACKGROUND 
     Belt conveyor systems use belts to convey items. Conventional belt conveyor systems use rollers, guides, and other mechanisms to orient the belt or to maintain tension on the belt. For example in a curved conveyor system, guides, rollers, and other mechanisms are used to maintain tension on the belt. Without the tension, the belt will become unstable, which will cause the conveyor to fail. 
     The aforementioned rollers, guides, and other mechanisms used to orient the belt generate a great amount of friction. This friction increases the power required to operate the conveyor in addition to the amount of noise generated by the conveyor. The mechanisms also limit the speed at which the conveyors, especially curved conveyors, can operate. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of an embodiment of a conveyor system. 
         FIG. 2  is a perspective view of the first end of the conveyor system of  FIG. 1  showing some of the internal components of the conveyor system. 
         FIG. 3  is a top view of the conveyor system of  FIG. 1  with the belt removed. 
         FIG. 4  is an exploded view of an embodiment of a portion of a chain used in the conveyor system of  FIG. 3 . 
         FIG. 5  is a bottom view of an embodiment of the conveyor system of  FIG. 1 . 
         FIG. 6  is a side cutaway of another embodiment of a portion of the conveyor system of  FIG. 1 . 
         FIG. 7  is a side cut away view of an embodiment of the return path of the conveyor of  FIG. 1 . 
         FIG. 8  is a top view of an embodiment of a chain retainer. 
         FIG. 9  is a side view of the chain retainer of  FIG. 8 . 
         FIG. 10  is a side cut away view of an embodiment of a conveyor. 
         FIG. 11  is a top perspective view of an embodiment of a magnet block of the conveyor of  FIG. 10 . 
         FIG. 12  is a top plan view of an embodiment of the chain of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION 
     Conveyor systems using magnetic forces to orient a belt and provide tension on a belt are described herein. One embodiment of such a conveyor system is shown in  FIG. 1 , which is a top plan view of a belt-type conveyor system  100  (sometimes simply referred to as a conveyor  100 ). The conveyor system  100  is a horizontal, curved conveyor. However, the conveyor  100  may be virtually any other type of conveyor, such as a straight conveyor, a conveyor that is not horizontal, a spiral type conveyor, or a conveyor that turns 180 degrees. 
     The conveyor  100  has a first end  102  and a second end  104 , wherein items are conveyed between the first end  102  and the second end  104 . Because the conveyor  100  of  FIG. 1  is curved, items may enter the first end  102  traveling in a first direction  108  and exit the second end  104  traveling in a second direction  110 . The angle between the first direction  108  and the second direction  110  may be virtually any angle. In a straight conveyor, the first direction  108  is substantially the same as the second direction  110 . 
     The conveyor system  100  has an outer frame  114 , sometimes referred to as a first member, and an inner frame  116  located opposite the outer frame  114 . The outer frame  114  and the inner frame  116  may extend at least partially between the first end  102  and the second end  104  of the conveyor  100 . Both the first end  102  and the second end  104  may have pulleys or rollers located therein and are described in greater detail below. 
     With additional reference to  FIG. 2 , which is a view of the conveyor system  100  of  FIG. 1  with the belt (described below) removed, the conveyor system  100  has two rollers  117 ,  118 . A first roller  117  is located proximate the first end  102  and a second roller  118  is located proximate the second end  104 . The rollers  117 ,  118  may extend substantially between the outer frame  114  and the inner frame  116 . Because the conveyor system  100  described herein is curved, the rollers  117 ,  118  are tapered in order to accommodate a conical-shaped belt. In some embodiments, pulleys may be used in place of at least one of the rollers  117 ,  118 . A platform  119  extends between the first roller  117  and the second roller  118  and is used to support the belt as described below. It is noted that other support mechanisms, such as rollers and the like, may be used to support the belt. In some embodiments, the platform  119  rolled or formed in the shape of a roller, thus, alleviating the need for the rollers  117 ,  118 . 
     A continuous belt  120  extends and travels between the first end  102  and the second end  104 . More specifically, the belt  120  passes over the aforementioned rollers  117 ,  118 . The belt  120  has a first side  122  and a second side  124 , which is opposite the first side  122 . The first side  122  is located proximate the outer radius of the conveyor curve and the second side  122  is located proximate the inner radius of the conveyor curve. As described above, the belt  120  sets and slides on the platform  119 . The belt material and platform material may be chosen to have a low coefficient of friction. 
     Due to the nature of curved conveyors, the tension of the belt  120  must be maintained on the rollers  117 ,  118 , otherwise, the belt  120  will slip off the rollers  117 ,  118 . More specifically, a force in the direction  121  along the radius of the curved conveyor  100  must be maintained. The conveyor  100  described herein uses magnetic forces to maintain the belt first side  122  proximate the outer frame  114 , which serves to maintain belt tension on the rollers  117 ,  118 . 
     Conventional conveyors, including curved conveyors, are limited in the speed at which the belt can travel because they use rollers and/or guides, and other mechanisms, to maintain the belt first side proximate the outer frame. These rollers, guides, and other mechanisms have friction, which limits the speed at which the belt can travel. The friction also causes the belt to become unstable at high speeds. In addition, the friction requires a great amount of power to move the belt. The friction also generates substantial noise when the conveyor operates. As described in greater detail below, the conveyor  100  described herein overcomes these problems by replacing the rollers, guides, and other mechanisms with magnets and/or magnetic forces. Therefore, frictionless magnetic forces are used to maintain the belt first end  122  proximate the outer frame  114 . 
     An exploded view of the first end  102  of the conveyor  100  is shown in  FIG. 3 . The view of  FIG. 3  has covers removed so that the components within the conveyor  100  are visible. The conveyor  100  includes a movement mechanism, which in the embodiment of  FIG. 3  is a chain  130 . The chain  130  is connected to the belt  120  by way of a plurality of first connectors  132 . The chain  130  is also connected to a plurality of magnets  142  by way of a plurality of second connectors  140 . 
     An exploded view of an embodiment of the chain  130  is provided in  FIG. 4 . As shown in  FIG. 4 , the first connectors  132  and the second connectors  140  may be links within the chain  130 . It is noted that in some embodiments, the second connectors  140  may be connected to magnetic materials or magnets. In some embodiments, the first connectors  132  and the second connectors  140  may be a single unit attached to the chain  130 . It is noted that drive mechanisms other than the chain  130  may be used within the conveyor  100 . For example, the chain  130  may be replaced by a cable. 
     Referring again to  FIG. 3 , located proximate the magnets  142  is a first rail  146 . The first rail  146  may be fixed relative to the outer frame  114 . In some embodiments, the first rail  146  is comprised of magnetic material. In some embodiments, the first rail  146  comprises a plurality of magnets. Regardless of the magnet configuration, magnetic force attracts the second connectors  140  to the first rail  146 . Accordingly, a force is applied on the belt  120  in the direction  121  by the magnetic forces. In some embodiments, the magnets  142  are configured so that a first polarity faces the first rail  146 . The first rail  146  is magnetized or has magnets located therein so that the polarity opposite the first polarity faces the magnets  142 . 
     The rail  146  is shown as being offset or spaced from the outer frame  114 . This spacing prevents magnetic material, such as steel, within the conveyor  100  from acting upon or adversely affecting the above-described magnetic forces. In some embodiments, the rail  146  may be attached to the outer frame  114 . In other embodiments, a nonmagnetic material, such as aluminum or stainless steel, may be placed between the rail  146  and the outer frame  114 . 
     A drive mechanism, such as a motor moves the chain  130 , which moves the belt  120 . In addition, the chain  130  may be connected to the rollers  117 ,  118 ,  FIG. 2 . In these embodiments, the first roller  117  may be attached to a sprocket  150 , which is also connected to the chain  130 . Thus, as the chain  130  moves, the first roller  117  also moves. In other embodiments, the first roller  117  is not connected to the sprocket  150  and the first roller  117  moves by way of movement of the belt  120 . The sprocket  150  may then serve to guide the chain  130  and may also be connected to the drive mechanism so as to drive the chain  130 . 
     The magnetic forces described above maintain the first belt end  122  proximate the outer frame  114  without the use of rollers, guides, or other devices, which significantly reduces friction and the above-described problems associated with friction. Therefore, as the belt  120  moves, the belt first end  122  is forced toward the outer frame  114  by the magnetic forces. This situation enables the belt first end  122  to remain taunt without friction generating devices. It is noted that the magnetic forces also support the belt first end  122  in the vertical direction so sagging of the belt first end  122  is minimized. Supporting the belt  120  in the vertical direction may be accomplished by selecting the magnets  142  and the rail  146 . For example, if the magnets  142  have substantially the same height as the rail  146 , the vertical position of the belt  120  is better maintained. 
     In some embodiments, a chain rail  154  may be provided. 
     The chain rail  154  may extend the length of the conveyor system  100  and serves to keep the chain  130  from oscillating or becoming unstable. The chain rail  154  may slightly contact the chain  130  and may be made of a material that has very low friction relative to the chain  130 . In some embodiments, the chain  130  rolls on the chain rail  154 . 
     Having described the top portion of the conveyor  100 , the bottom portion will now be described. When the belt  120  is described in the lower section of the conveyor  100 , it is referred to as being in the return path. Accordingly, the return path refers to the path of the belt  120  when it is not conveying items. In some embodiments, the magnet and rail system described above may be used to support the belt  120  in the return path. Because the return path does not necessarily have a platform to support the belt  120 , rollers or pulleys (not shown in  FIG. 5 ) may be provided to support the belt. The rollers or pulleys may extend between the outer frame  114  and the inner frame  116 . The number and type of rollers is a design consideration and may depend on the type of belt, the length of the conveyor, the speed of the belt, and other considerations. Other embodiments of the return path will be described below. 
     Having described some embodiments of the conveyor system  100 , its operation will now be described. Other embodiments of the conveyor system  100  will be described further below. Referring to  FIGS. 1-3 , the belt  120  is maintained in position by the magnetic forces exerting a force on the belt  120  in the direction  121 . The force of the belt  120  is applied to the tapered rollers  117 ,  118 . Therefore, the belt  120  is kept in constant tension by the magnetic forces. The amount of tension may be controlled by the flux of the magnets used therein and the distance between the second connectors  140  and the first rail  146 . 
     A drive mechanism moves the chain  130 , which is connected to the belt  120  via the first connectors  132 . Thus, the belt  120  moves as the chain  130  moves. As the belt  120  moves, it slides on the platform  119  and rolls on the rollers  117 ,  118 . In the return path, the belt  120  may be supported by rollers as described above. Therefore, during operation, the only friction in the conveyor  100  is in the drive mechanism, the rollers  117 ,  118 , and between the platform  119 , and the belt  120 . Therefore, the power required to operate the conveyor  100  is much less than the power required to operate a conventional conveyor. In addition, the noise of the conveyor  100  is much less than the noise of a conventional conveyor. The use of the magnetic forces to maintain the belt  120  in tension stabilizes the belt  120  relative to conventional conveyors. Therefore, the belt  120  is able to operate at higher speeds than belts used in conventional conveyors. 
     Some embodiments of the conveyor of  FIGS. 1-3  will now be described. Different magnetic configurations between the first rail  146  and the second connectors  140  may be used. For purposes of this specification, the term magnetic material is a material, such as iron or steel, that is attracted to a magnet or acts under a magnetic force. The embodiments described above have magnets attached to the second connectors  140  and the first rail  146  is magnetic or has magnets located therein. In another embodiment, the first rail may be comprised of a magnetic material such that the magnets  142  attached to the second connectors  140  are attracted to the first rail  146 . In another embodiment, the first rail is magnetic, the second connectors  140  comprise magnetic material, and the magnets  142  are not used. In this embodiment, the magnetic first rail  146  attracts the second connectors  140 . In some embodiments, the chain  130  is made of a magnetic material, which increases the magnetic attraction to the first rail  146 . 
     A side cutaway view of another embodiment of the conveyor  100  is shown in  FIG. 6 . In this embodiment, two magnetic rails  146 ,  160  are provided in order to increase the magnetic force applied to the second connectors  140 . The second connectors  140 , the magnets  142 , and the first rail  146  may be the same as described above. However, the second connectors  140  may be made of a nonmagnetic material, such as stainless steal. The magnets  142  have a first face  160  having a first polarity and an opposite face  162  having the opposite polarity. The first rail  146  has a face  164  that is polarized opposite the polarity of the first face  160  of the magnets  142 . Thus, there is magnetic attraction between the magnets  142  and the first rail  146 . Additional magnetic force is generated by the second rail  160 . The second rail  160  has a face that is magnetized, or has magnets located therein, with a polarity that is the same as the polarity of the second face of the magnets  142 . Therefore, the second rail increases the magnetic force applied to the connectors  140  via a magnetic repulsion force. 
     An alternate version of the return path is shown in  FIG. 7 , which is a partial cutaway view of the association between the second connectors  140  and the rail  146 . In this embodiment, a second magnet  170  is mounted to the first connector. The second magnet  170  has a face  172  that is polarized. A third rail  174  is provided proximate the second magnet  170 . The third rail  174  has a face  176  that is magnetized with the same polarity as the face  172  of the second magnet  170 . The configuration of the second magnet  170  and the third rail  174  serves to repel the second connector  140 , which supports the belt  120  in the vertical direction in the return path. 
     The conveyor  100  has been described as a curved conveyor. However, it is possible to use the magnetic forces in a straight conveyor. In a straight conveyor, forces are not required to pull on the sides of the belt as this tension is not as critical. Therefore, magnetic configurations as shown in  FIG. 6  may be employed with both rails  146 ,  160  repelling the magnets  142 . Accordingly, the face  164  of the first rail  146  may be polarized so as to be the same as the first face  160  of the magnets  142 . Such a configuration will orient the belt in a straight conveyor. In a similar embodiment, both sides of the belt and conveyor may have magnetic configurations as described above. 
     Some uses of the conveyor  100  may cause the belt  120  ( FIG. 2 ) to move slightly in a direction opposite the direction  121 . For example, if a heavy load is suddenly placed on the belt  120 , the belt may move slightly in the direction opposite the direction  121 . Because magnetic force is exponentially proportional to distance, this slight shift of the belt may cause the magnets  142  to be out of the effective range of the first rail  146 . In order to overcome this issue, the conveyor  100  may have a chain retainer  200  or a plurality of chain retainers  200  located therein. In summary, the chain retainer  200  prevents the chain  130 , and thus, the magnets  142  from moving too far from the first rail  146 . Therefore, the magnets  142  are always maintained within an effective distance of the first rail  146 . 
     A top view of an embodiment of the chain retainer  200  is shown in  FIG. 8  and a side view of the chain retainer  200  is shown in  FIG. 9 . The chain retainer  200  is fixed to a chassis member or other non-movable device within the conveyor  100 . The chain retainer has at least one roller  204  that is able to contact the chain  130 . The embodiment of the chain retainer  200  described herein has two rollers  204 . The rollers  204  may contact the chain  130  during operation or when the belt  120  moves as described above. The use of the rollers  204  adds very little friction and noise to the conveyor  100 , so the use of the chain retainer  200  has very little impact on the operation of the conveyor  100 . In some embodiments, low friction elements, such as plastic or nylon type devices are used in place of the rollers  204 . 
     The chain retainer  200  has a first plate  210  that mounts to a chassis as described above. A second plate  212  is movably attached to the first plate  210 . Retainers  214  are movable in slots  216 , which allow the second plate  212  to move relative to the first plate  210 . The movement enables the chain retainer  200  to maintain the position of the chain at very precise points. 
     The number of chain retainers  200  used in a conveyor depends on the radius of the conveyor, the shape of the conveyor and the loads placed on the conveyor. For example, a u-shaped conveyor transporting heavy loads may need three. A ninety degree turn conveyor may only need one. A straight conveyor may not need any. 
     It is noted that devices other than chains may move the belt  120 . Accordingly, the above-described chain retainer  200  may serve to act on these other devices in a substantially similar manner as the chain  130 . 
     Other embodiments of the conveyor  100  is shown in  FIG. 10 ,  FIG. 11 , and  FIG. 12 .  FIG. 10  is a side cut away view of an embodiment of the conveyor  100  using a repelling magnet configuration. For reference purposes, the conveyor  100  has an upper portion  250  and a lower portion  252 . The upper portion  250  is used by the conveyor to move items via the belt  120 . The lower portion  252  is a return path for the belt  120 . 
     In the embodiments of  FIGS. 10-12 , the belt  120  may be attached to the chain  130  by way of a plurality of connectors  256 . A top view of the chain  130  and a connector  256  is shown in  FIG. 12 . Magnet blocks  260  are connected to the connectors  256 . A side perspective view of a magnet block  260  is shown in  FIG. 11 . The magnet block  260  has a plurality of planes or surfaces with at least one magnet attached to each plane. In the embodiment of  FIGS. 10 and 11 , the magnet block  260  has three planes, a first plane  262 , a second plane  264 , and a third plane  266 . The first plane  262  may be substantially parallel to the third plane  266  and substantially perpendicular to the second plane  264 . The shape of the planes  262 ,  264 ,  266  may form a cavity or opening  270 . 
     Each of the planes  262 ,  264 ,  266  or surface may have at least one magnet (sometimes referred to as chain magnets) located thereon. In the embodiment of  FIG. 11 , the first plane  262  has two first magnets  271 ,  272  located thereon. In some embodiments, the first plane  262  may have a single magnet located thereon. The second plane  264  has a second magnet  274  located thereon. The third plane  266  has a third magnet  276  located thereon. All the magnets  271 ,  272 ,  274 ,  276  may be aligned so as to have the same pole facing the opening  270 . For example, all the magnets  271 ,  272 ,  274 ,  276  may have their norths facing the opening  270 . It follows that the magnets  271 ,  272 ,  274 ,  276  have the same pole facing opposite the opening  270 . 
     With additional reference to  FIG. 10 , magnets (sometimes referred to as conveyor magnets) are located in the conveyor  100  so as to repel the magnets  271 ,  272 ,  274 ,  276 , which forces the belt  120  toward the outer frame  114 . The upper portion  250  has magnets facing the magnet block magnets so as to repel the magnet block magnets. A first magnet  280  (or plurality thereof)+faces the first magnets  271 ,  272  of the magnet block  260  so as to force the magnet block  260  in a direction  282 . A second magnet  284  is located proximate the second magnet  274  of the magnet block  260  and forces the magnet block  260  in a direction  288 . A third magnet  290  is located proximate the third magnet  276  on the magnet block  260  and forces the magnet block  260  in a direction  294 . The repelling forces between the magnets in the magnet block  260  and the magnets attached to the outer frame  114  force the magnet block, and the belt  120  toward the outer frame  114 . The repelling force also causes the chain  130  to float. Accordingly, the chain  130  is able to move without contacting supporting structures. Therefore, it moves with very little friction. 
     A similar magnetic structure exists in the lower portion  252  of the conveyor  100 . A first magnet  296  is located proximate the first magnets  271 ,  272  of the magnet block  260  and forces the magnet block  260  in the direction  294 . A second magnet  298  is located proximate the second magnet  274  on the magnet block  260  and forces the magnet block  260  in the direction  288 . A third magnet  300  is located proximate the third magnet  276  on the magnet block  260  and forces the magnet block  276  in the direction  282 . Accordingly, the chain  130  on the return path is maintained by the magnetic forces and encounters very little structures. Thus, it moves with little friction. 
     The upper portion  250  and the lower portion  252  may have a plurality of magnets located therein. For example, the above described magnets may extend the distance or a portion of the distance of the outer frame  114 . As shown in  FIG. 10 , the magnets may be located in slots or other devices (sometimes referred to as members) similar to those described above. 
     The embodiments of  FIG. 10  use a magnetic repulsing force to force the belt  120  toward the outer frame  114 . As the belt  114  encounters a load, it will be forced away from the outer frame  114 . However, when this happens, the second magnet  274  in the magnet block  260  will move closer to the second magnet  284 . Because the repulsive force is inversely proportional to distance, the closer the magnets  274 ,  284  get to each other, the greater the magnetic force that act to force the belt  120  back toward the outer frame  114 . 
     In some situations, the repulsive force between the magnets  274 ,  284  will cause the magnetic block to move in the directions  282 ,  294 . If this movement occurs, the magnetic force between the magnets  274 ,  284  will attenuate significantly. The magnetic forces of the first magnets  271 ,  272  and the first magnet  380  keep the magnetic block  260  from moving in the direction  294  or keep the magnetic block  260  within boundaries. The repulsive force between the third magnet  276  and the third magnet  290  acts in a similar manner by limiting the movement of the magnet block  260  in the direction  282 . Therefore, as the magnet block  260  moves away from the outer frame  114 , the second and third magnets maintain its position so that the second magnets  274 ,  284  can repel each other.