Patent Description:
The invention relates generally to power-driven conveyors and more particularly to the conveyance of articles containing an electrically-conductive material.

Conveyors are often used to transport articles through a manufacturing process. In some circumstances, the transportation of aluminum beverage cans through a can manufacturing process can be difficult in transition points, where the cans need to be transferred from one process step to the next. The lightweight cans are fragile and may be prone to tipping, which makes them susceptible to stranding on transfer dead plates. Such problems require manual intervention by operators, which can increase cost and risk potential contamination. In addition, the stranding of cans on the process line can result in costly mixing of can batches if all stranded cans are not removed from the process line.

<CIT> discloses a conveying device for goods.

<CIT> discloses a non-ferrous metal can conveyor.

<CIT> discloses a stagnating device for a metallic can. The document discloses the features of the preamble of claim <NUM> and furthermore discloses a method of transferring aluminium cans from a first conveyor through a transfer zone to a second conveyor, comprising the steps of: conveying aluminium cans along a product path at a first conveyance speed; and generating a repelling force on the aluminium cans to guide the aluminium cans along the product path using a touchless guide device comprising a linear induction motor.

One version of a conveyor embodying features of the invention comprises a conveyor belt and a touchless guide device that generate a repelling force to guide products along a product path in a conveyor.

According to one aspect of the invention, a conveyor according to claim <NUM> is provided.

According to another aspect, a method according to claim <NUM> is provided.

These aspects and features of the invention are described in more detail in the following description, appended claims, and accompanying drawings, in which:.

A conveyor employs a guide device for generating a repelling force to propel product along a product path with little or no contact. The guide device may comprise a linear induction motor, permanent magnet array or other device that generates a repelling force to repel the product away from the guide device and along the product path with little or no contact with the product. Aspects of the invention will be described with reference to certain illustrative embodiments, though the invention is not limited to those illustrative embodiments.

A portion of a conveyor is shown in <FIG>. The conveyor <NUM> transports products along a product path and comprises a first conveyor belt <NUM> that advances in a first direction of belt travel <NUM>. At a transfer or junction point <NUM>, product is transferred to a second conveyor belt <NUM>, which receives product from the first conveyor belt <NUM> and conveys the product in a second direction of belt travel <NUM>. The belt may be driven by any conventional drive means, such as sprockets <NUM>, motor-driven drums, pulleys, or by a linear induction motor. Idle sprockets or guide elements (not shown) may be used to guide the conveyor belts, as known in the art.

The conveyor <NUM> may employ a touchless rail or device for guiding conveyed product along the product path while minimizing damage to the conveyed product. For example, the illustrative conveyor <NUM> includes a touchless rail <NUM> at the transfer point <NUM> adjacent to the product path for guiding conveyed product from the first conveyor belt <NUM> to the second conveyor belt <NUM>. In the illustrative example, the conveyed product comprises aluminum cans <NUM> or another product containing a conductive material, and the touchless rail <NUM> generates a repelling force, in addition to a translational force, to push the aluminum cans towards the second conveyor along a desired product path with little to no contact force.

In the example of <FIG>, the touchless rail <NUM> comprises a first rail <NUM> oriented at a first angle and positioned over the first conveyor belt <NUM> adjacent to a product path, and a second rail <NUM> adjacent to and in series with the first rail <NUM>. The first rail <NUM> is shown as oriented transverse to the first direction of travel <NUM>, preferably at an obtuse angle. The illustrative second rail <NUM> forms a side rail on the second conveyor belt <NUM> that is substantially parallel to the second direction of travel <NUM>.

In the example of <FIG>, each rail <NUM>, <NUM> is a linear induction motor (LIM) comprising a shaped multi-phase induction coil that generates a repelling force to push conveyed articles containing a conduct material through the transfer zone. Any suitable arrangement of coils may be used to generate the repelling force. For example, in one example, discrete coils are arranged in a directional arrangement to guide articles that include or are formed of an electrically conductive material, such as the aluminum cans <NUM>, in a desired direction and force the articles onto the second conveyor belt <NUM> or along another selected product path. The LIM coil forms a stator, and the electrically conductive material in the cans forms a conductor, which is pushed away from the stator by opposing fields generated in the stator and conductor.

In one example, the coils of the LIM have a series of poles that are energized to create a magnetic field. The magnetic field propagates down the coil in a propagation direction <NUM>. The propagating magnetic field passes through the conductive material in the cans <NUM> adjacent to the rails <NUM>, <NUM> and induces a current in the cans opposing the magnetic field. The interaction of the primary magnetic field from the LIM <NUM>, <NUM> with the induced current in the product produces a repelling force pushing the product in a selected direction without requiring much or any direct contact. Preferably, the repelling force repels the cans away from the rails <NUM> or <NUM> and pushes the cans through the transfer zone <NUM>. In this way, product will be pushed from the first belt <NUM> to second belt <NUM> with low contact force, which prevents tipping of the cans and promotes transfer of the cans in the upright position. The vector of the repelling force depends on the particular design of the rail. Generally, the repelling force vector will be less than about <NUM>° from the surface of the LIM.

A plurality of coils in the LIM rails <NUM>, <NUM> could form discrete stators, arranged to produce a desired trajectory, or one or more coils could be shaped to produce a desired trajectory.

The guide rails <NUM>, <NUM> may distribute repelling forces along the full-vertical breadth of the LIM allowing the guide rail to guide the path of the product without mechanically touching the product or risking damage to thinner gauge cans. The net force may be applied to the can center of mass to prevent tipping.

The LIM drives may be synchronized to the belt speeds, or may be synchronized to provide a change in the speed at which the product is conveyed in select locations. For example, discrete articles may be conveyed faster than other articles. The LIM speeds can be adjusted to achieve a desired product speed and-or trajectory through a conveyor.

<FIG> illustrates another example of a touchless rail for guiding products, such as aluminum cans in a conveyor <NUM> through a transfer zone <NUM> between a first conveyor belt <NUM> moving in a first direction <NUM> and a second conveyor belt <NUM> moving in a second direction <NUM>. The touchless rail <NUM> of <FIG> comprises a curved linear induction motor (LIM) that curves along product path through the transfer zone <NUM>. The curved rail <NUM> employs a singled coil shaped in a circular arc, or multiple coils arranged in an arc. The illustrative arc is <NUM>°, though the invention is not so limited. The curved rail <NUM> generates a propagating magnetic field that induces opposing currents in a conveyed product, illustrated as aluminum cans <NUM>, creating a repelling force on the aluminum cans to propel the cans through a transfer zone <NUM> and onto the second conveyor belt <NUM>.

Other sources can be used to generate the repelling force. For example, <FIG> shows a conveyor <NUM> having a touchless guide rail in a transfer zone <NUM>, the touchless guide rail formed using an array of permanent magnets <NUM>. The first conveyor belt <NUM> moves in direction <NUM>. As a first conveyor belt <NUM> brings the product containing a conductive material, such as aluminum cans <NUM>, past the array <NUM>, the permanent magnet array creates a magnetic field that induces eddy drag on the outer cans closest to the array <NUM>, facilitating transfer of the cans onto a second conveyor belt <NUM>, moving in direction <NUM>, with low contact force. One skilled in the art will be able to determine a suitable size, strength, orientation of the magnets to sufficiently repel the cans and propel the cans along a desired trajectory. The magnets in array <NUM> may have alternating polarity, the same polarity or comprise a Halbach array.

<FIG> shows the progression of cans <NUM> through the transfer zone <NUM>. As shown, the repelling force generated by the magnetic array <NUM> retards the motion of the outer cans, causing fluid motion of the can group, reducing pressure on the individual cans.

In another example, a conveyor includes one or more touchless side rails for guiding product along a product path, as shown in <FIG>, <FIG> and <FIG>. In the embodiment of <FIG>, a conveyor belt <NUM> moving in direction <NUM> includes one or more side rails <NUM>, <NUM> comprising a permanent magnet array. The side rails <NUM>, <NUM> are adjacent to the product path. As the conveyor belt <NUM> moves the product, illustrated as a collection of aluminum cans <NUM>, past the rails <NUM>, <NUM>, the permanent magnet arrays induces an eddy drag on the outer cans <NUM> in the set of conveyed aluminum cans, allowing the inner cans <NUM> to flow forward, similar to fluid in a pipe. The eddy drag in the outer cans <NUM> cushions the cans and protects them from damage while promoting conveyance of the cans along the product path.

As shown in <FIG> and <FIG>, in another example, a conveyor belt <NUM> moving in direction <NUM> includes side rails <NUM>, <NUM> comprising linear induction motors (LIMs). The LIMs <NUM>, <NUM> generate a repelling force on outer cans <NUM> in a set of aluminum cans <NUM>, repelling the outer cans from the side rails <NUM>, <NUM> to reduce potential damage while causing the inner cans <NUM> to flow forward.

<FIG> are sequential top views of a guide device <NUM> and aluminum can <NUM> during propagation of a magnetic field. The field V propagates from left to right, creating a field shown by the field lines <NUM>, which induce currents in the can <NUM>. <FIG> shows a can <NUM> having currents I induced by the guide device <NUM> according to one example.

The induced currents in the can generate a field opposing the field generated by the guide device <NUM>, causing the can to be propelled forward and rotated in the direction of ω. Generally, the net force would be at about a <NUM>° angle from the face of the coil <NUM>.

<FIG> and <FIG> show an embodiment of a touchless guide adjacent a product path for guiding product along the product path in a conveyor. In the embodiment of <FIG> and <FIG>, the touchless guide <NUM> is disposed below the product path to motivate the cans, or other product, from the bottom direction. The conveyor <NUM> of <FIG> and <FIG> comprises a first conveyor belt <NUM> moving in direction <NUM>, a second conveyor belt <NUM> moving in direction <NUM> and a junction zone <NUM> between the first and second conveyor belt comprising a plurality of curved rails <NUM>, <NUM>, <NUM> below the product path in the junction zone <NUM>. Each curved rail <NUM>, <NUM>, <NUM> comprises a linear induction motor (LIM). As shown in <FIG>, a low friction surface <NUM> is disposed directly above the rails <NUM>, <NUM>, <NUM> to form the product path in the transfer zone <NUM>. The curved LIMs are activated to propel the cans <NUM> around and through the <NUM>° junction zone <NUM>.

<FIG> shows another example of a conveyor <NUM> employing a touchless guide for guiding product along an adjacent product path. The touchless guide <NUM> of <FIG> comprises an array of linear induction motors (LIMs) <NUM>. A low friction surface <NUM> directly above the array <NUM> forms the product path of the conveyor <NUM> in a transfer zone <NUM>. The LIMS <NUM> have varying drive angles to drive the cans en masse from the bottom around the <NUM>° transfer zone <NUM> between a first conveyor belt <NUM> and a second conveyor belt <NUM>.

The use of a touchless guide, such as a LIM or array of alternating permanent magnets, to generate repelling forces on delicate conveyed products ensures a smooth transfer between belts or smooth conveyance on a single belt. The touchless guide may prevent tipping and minimize damage. With few or no moving parts, the touchless guide is cleanable and requires little to no maintenance.

Claim 1:
A conveyor (<NUM>) for aluminium cans (<NUM>), comprising:
a first conveyor belt (<NUM>) for conveying aluminium cans (<NUM>) along a product path moving in a first direction (<NUM>);
a second conveyor belt (<NUM>) moving in a second direction (<NUM>);
a guide device (<NUM>) for touchlessly guiding the aluminium cans (<NUM>) along the product path without mechanically contacting the aluminium cans (<NUM>);
wherein the touchless guide (<NUM>) is disposed below the product path to motivate the aluminium cans (<NUM>) from the bottom direction;
a junction zone (<NUM>) between the first and second conveyor belts (<NUM>, <NUM>);
a low friction surface (<NUM>);
characterized in that,
the touchless guide (<NUM>) comprises a plurality of curved rails (<NUM>,<NUM>,<NUM>); wherein the junction zone (<NUM>) comprises the plurality of curved rails (<NUM>,<NUM>,<NUM>) below the product path in the junction zone (<NUM>);
the low friction surface (<NUM>) is directly above the curved rails to form the product path in the junction zone (<NUM>);
wherein each curved rail (<NUM>, <NUM>, <NUM>) comprises a linear induction motor; and wherein the curved linear induction motors are activated to propel the aluminium cans (<NUM>) around and through the <NUM>° junction zone (<NUM>).