Patent Description:
Current methods of processing meat, fish, or poultry require cutting bulk product by hand. For example, the bulk meat is conveyed to an operator who loads the meat onto a tray. The operator then cuts the meat into defined portions on the tray's cutting surface. The tools used to cut the meat can score and scratch the cutting surface. Trays marred by scratched surfaces are difficult to sanitize-especially if the trays are sanitized manually. Biofilms, which are especially difficult to remove, can form on and contaminate the trays.

A tray conveyor embodying features of the invention comprises a track having an array of electromagnetic drive coils extending along the length of the track and a coil driver driving the drive coils to produce an electromagnetic flux wave that travels along the length of the track along a conveying path defined by the drive coils. A tray conveying products through a process includes a top and a bottom. A permanent magnet array between the top and the bottom produces a magnetic field that interacts with the traveling electromagnetic flux wave to produce a force that propels the tray along the track. An ice coating covers at least the top of the tray. Products sit atop the ice coating on the top when the products are undergoing the process. The tray conveyor furthermore comprises a freezer producing an ice cover and a cover applicator on the conveying path depositing the ice cover on the top of the tray to form the ice coating.

In another aspect, a method for conveying products through processing using a tray conveyor as previously described comprises: (a) advancing a magnetic tray along a track with a linear motor drive; (b) adding an ice coating to cover the top of the tray by freezing an ice cover and putting it on top of the tray;
(c) loading a product onto the ice coating atop the tray; (d) processing the product; (e) removing the product from the tray during or after undergoing the process; (f) removing at least a top layer of ice from the ice coating covering the top of the tray; and (g) repeating steps (c) through (f).

<CIT> discloses a conveyor system for conveying objects having at least one rail having a top wall and extending along a path; a number of electromagnets housed inside the rail; control means for sequentially operating the electromagnets; and at least one support for supporting the objects, and which is movable on the rail to transport the objects, has a bottom wall, and has at least one permanent magnet inside; the permanent magnet, in use, being designed to interact with the electromagnets in the rail to move the support on said rail; and the support is connected to the rail so that the bottom wall of the support rests on and, in use, slides on the top wall of the rail.

<CIT> discloses an XY table for a linear transport system, having a carriage-guide rail which has a curved portion, designed so that, when a first and a second linear guide of the XY table are oriented parallel to the track plane of the carriage-guide rail, first guide elements of the first and second linear guides are connected to a carrying structure of the XY table and/or a second guide element of the first linear guide is connected to a first carriage, and a second guide element of the second linear guide is connected to a second carriage, such that rotation is possible in the track plane of the carriage-guide rail, or so that, when a first and a second linear guide are oriented in a plane of orientation perpendicular to the track plane of the carriage-guide rail <NUM>, first guide elements of the first and second linear guides are connected to a carrying structure of the XY table and/or a second guide element of the first linear guide is connected to a first carriage, and a second guide element of the second linear guide is connected to a second carriage, such that tilting is possible in the plane of orientation.

<CIT> discloses the features of the preamble of claim <NUM> and in particular discloses a transport system powered by short block Linear Synchronous Motors (LSMs).

<CIT> discloses a tray conveyor in which plastic trays with rows of embedded translators are driven by stators. Washing stations in cleaning zones are provided to automatically clean empty trays in the conveyor's return path.

<FIG> show one version of a tray conveyor embodying features of the invention. The tray conveyor <NUM> has a track <NUM> that defines a conveying path. In this example, the track <NUM> has a pair of parallel rails <NUM>, 24R supported by legs <NUM> along the length of the track. In right-angle corner sections <NUM> of the track <NUM>, the track rails <NUM>, 24R cross each other at a <NUM>° angle. The corners could alternatively be made of curved track sections without crossing track rails.

Magnetic trays <NUM> are independently propelled along the track <NUM> by linear stator coils in the track rails <NUM>, 24R. The trays <NUM>, shown in more detail in <FIG>, have a top <NUM> and an opposite bottom <NUM> sandwiching a permanent magnet layout <NUM>. An electrically conductive aluminum or copper plate <NUM> is optionally sandwiched between the top <NUM> and the permanent magnet array <NUM>. The top <NUM> and the bottom <NUM> may be made of a rigid, nonmagnetic, corrosion-resistant material. For example, stainless steel top and bottom covers can form the tray's top and bottom. The permanent magnet layout <NUM> shown in <FIG> has four magnet arrays 40A-40D, each extending along a different side of the rectangular tray <NUM>. The magnet arrays 40A-40D can be arranged as Halbach arrays to focus the magnetic field toward the tray bottom <NUM>. The top <NUM> of the tray <NUM> in <FIG> may be covered with a pre-made ice cover <NUM> with a recess <NUM> in which the tray fits.

As shown in <FIG>, the two track rails <NUM>, 24R each have linear stator coils <NUM> extending along the length of the track. The electromagnetic drive coils <NUM> shown enlarged in <FIG> are driven by a coil driver to produce an electromagnetic flux wave that travels along the length of the track rails <NUM>, 24R. The traveling flux wave interacts with the magnetic field of the permanent magnet arrays in the trays to produce a force propelling the trays along the track. Position sensors <NUM>, such as Hall-effect sensors, are periodically spaced along the length of the linear stator coils <NUM> at predetermined sensor positions to detect the presence of a tray at the sensor positions. The position sensors <NUM> are used by the coil driver to drive the coils with a commutated current as a brushless de motor. As one alternative, the magnetic trays could be driven as a synchronous linear ac motor. The lateral spacing of the permanent magnet arrays along opposite sides of the trays matches the lateral spacing of the electromagnetic drive coils for effective magnetic coupling. If a single-rail track is used instead, the trays would need only a single permanent magnet array in line with the drive coils in the rail. The single rail can be a wide rail whose width is less than, equal to, or greater than the width of the tray and could have a single stator or a pair of stators.

<FIG> shows a corner section <NUM> of the conveyor in greater detail. The drive coils 46A in a first track segment 22A produce an electromagnetic flux wave traveling in a first conveying direction 50A. The drive coils 46B in a second track segment 22B perpendicular to and intersecting the first track segment 22A propagate an electromagnetic wave in a second direction 50B <NUM>° from the first direction 50A. When a tray as in <FIG> is completely on the corner section, its two pairs of permanent magnet arrays are aligned under the pairs of intersecting rails on each track segment 22A, 22B. The drive coils 46A on the first track segment 22A are then de-energized, and the drive coils 46B on the second track segment 22B are energized to propel the tray in the new direction 50B.

As shown in <FIG>, trays <NUM>' with ice coatings covering at least their tops advance along a first track segment 22A with products <NUM> sitting on the ice coatings. The ice-coated trays <NUM>' proceed along the track segment 22A to a processing area where the products <NUM> are processed manually or robotically. Processed products <NUM> are transferred to a discharge conveyor <NUM>. Residual contaminants from the products reside on the ice coatings, which isolate the trays themselves from contamination. The tracks themselves could be coated in ice and periodically defrosted for improved hygiene. An ice refinisher or a defroster <NUM> on the conveying path removes a top layer or the entirety of the ice coatings along with the contaminants they hold.

<FIG> show various versions of ice refinishers acting on ice-coated trays <NUM>'. All the refinishers are shown with cameras <NUM> associated with vision systems to control the thickness of the top layer of ice removed from the ice coating. But the refinishers could operate without cameras and a vision system and remove a fixed amount or all of the ice coating. The ice refinisher <NUM> of <FIG> includes a trimming wheel <NUM> with a peripheral blade <NUM>. The wheel <NUM> is rotated by a motor <NUM> as the wheel moves side to side along the tray <NUM>' as it is driven in the conveying direction <NUM> by the drive coils in the track rails. The rotating and side-to-side oscillating wheel <NUM> cuts into the ice coating <NUM> covering the top of the tray <NUM>' to trim a top layer of ice.

The ice refinisher <NUM> of <FIG> is a heater that emits a flame or hot air at the top of the advancing tray <NUM>' to melt a top layer of the ice coating <NUM>. The ice refinisher <NUM> of <FIG> uses infrared lamps <NUM> directed at the ice coating <NUM> to melt a top layer. The ice refinisher <NUM> of <FIG> uses a fluid jet <NUM> of compressed air or water moving side to side across the tray <NUM>' to remove a top layer of the ice coating <NUM>. And the ice refinisher <NUM> of <FIG> heats up a resistance wire <NUM> extending across the width of the tray <NUM>' and movable in depth to melt a top layer of the ice coating <NUM>. <FIG> shows the ice refinisher <NUM> of <FIG> with a vacuum system <NUM> to remove melted ice and ice particles from the residual ice coating. The vacuum system <NUM> can be used with any of the ice refinishers. Once an ice refinisher has removed the contaminated top layer, the tray with the residual uncontaminated ice coating can be removed from the track and replaced back on the track upstream to convey another product through the process.

Instead of removing only a top layer of the ice coating as the ice refinisher can, a defroster can remove the entire ice coating. One example of a defroster is shown removing the ice coating in <FIG>. The defroster <NUM> includes a barrier <NUM> that extends across the conveying path and a linear-induction motor stator <NUM> above the rails <NUM>, 24R. A slot <NUM> in the barrier <NUM> extends upward from the rails a height slightly greater than the thickness of the magnetic tray <NUM>. Brackets <NUM> are attached between the barrier <NUM> and the stator <NUM> to support it above the rails <NUM>, 24R. A camera <NUM> and its associated vision system images the tray <NUM> under the stator <NUM> as in <FIG>. The energized rails <NUM>, 24R push the tray <NUM> against the stop <NUM>. The thickness of the ice coating <NUM> on the tray prevents the tray from passing through the slot <NUM>. The linear-induction motor stator coils <NUM> are energized to produce an electromagnetic field that induces eddy currents in the electrically conductive copper or aluminum plate (<NUM>, <FIG>). The eddy currents heat the plate, and that heat is conducted to the top <NUM> and the bottom <NUM> tray covers <NUM>, <NUM> as shown in <FIG>. The inductive heating melts the ice coating <NUM> from the inside out and defrosts the tray <NUM>. When the ice coating <NUM> is melted, the tray <NUM> can pass through the slot <NUM> as shown in <FIG>. The camera <NUM> and the visioning system can be used to de-energize the defroster's stator <NUM> when they detect no tray <NUM> in position against the stop <NUM>.

An infrared defroster <NUM> is shown in <FIG>. When the ice-coated tray <NUM>' reaches a tiltable track segment, a camera <NUM> and its associated vision system or another kind of position sensor detects the tray, and a tilt actuator (not shown) tilts the tray as indicated by the arrow <NUM> in <FIG>. When the tiltable track segment <NUM> is tilted, its stator coils are disconnected from the rail coil drivers and connected to direct-current coil drivers that generate an electromagnetic field to which the permanent magnet arrays in the tray <NUM> are attracted. The force of attraction prevents the tray <NUM> from sliding off the rails. Infrared lamps <NUM> direct their radiation at the ice coating <NUM> on the tilted tray <NUM>. As the ice coating melts, the water is shed from the tilted tray <NUM> by gravity. The camera <NUM> and its vision system are used to determine when the tray <NUM> is completely defrosted so that the tilt actuator can pivot the tiltable track segment <NUM> back to its untilted position. Once the track segment is back in the untilted position, the defrosted tray <NUM> can resume its advance along the conveying path.

Another defroster is shown in <FIG>. The defroster <NUM> is similar to that of <FIG>. One difference is that the barrier <NUM> and the defrosting stator <NUM> are "upside down," i.e., rotated <NUM>° about the conveying direction from their positions in <FIG>. A tray-flipping track segment <NUM>, such as an extended-range tiltable track segment as in <FIG>, flips the ice-coated tray <NUM>' <NUM>° while transferring it from a first track segment <NUM> to an adjacent laterally offset second track segment <NUM> as shown in <FIG>. The upside-down, ice-coated tray <NUM>' is blocked by the barrier <NUM> as shown in <FIG>. The second track segment <NUM> has a pair of lower passive guide rails <NUM>, 124R without stators. The lower rails <NUM>, 124R prevent the upside-down tray <NUM>' from falling. Upper guide rails <NUM>, 126R include the rail stators that push the tray <NUM>' against the barrier <NUM>. The defrosting stator <NUM> beneath the second track segment <NUM> inductively heats the electrically conductive plate in the tray <NUM>' to melt the ice coating. The melted ice falls from the tray without contaminating the downward-facing tray top <NUM>. As shown in <FIG>, once the ice coating is removed, the defrosted tray <NUM> passes through the slot <NUM> in the barrier <NUM>, and the flipping track segment <NUM> is pivoted back to its position in line with the first track segment <NUM>. A similar flipping track segment downstream of the defroster <NUM> rights the tray <NUM> with its top facing upward to continue along the conveying path.

If the tray <NUM> is covered with a conforming pre-made ice cover <NUM> as in <FIG>, a defroster can be replaced by an ice-cover remover <NUM> as shown in <FIG>. A flipping track segment <NUM>, like the one in <FIG> flips the tray <NUM> with its ice cover <NUM> upside down as shown in <FIG>. The ice cover <NUM> falls from the tray <NUM>. Once the ice cover <NUM> has been removed, the flipping track segment <NUM> returns to its position in line with the main track <NUM>, and the ice-free tray <NUM> advances along the track in the conveying direction.

Defrosted trays <NUM> exiting the defroster <NUM> in <FIG> are diverted from the main track 22A to a tray sanitizer <NUM> in a side track 22B. The sanitizer <NUM> sanitizes the ice-free trays <NUM>, which are then advanced along the side track 22B to a tray freezer <NUM>, which installs an ice cover on top of the tray. The ice-coated tray <NUM>' is driven back to the entrance end <NUM> of the main track 22A to receive product.

A flowchart of one way the tray conveyor can be operated is shown in <FIG>. First, at step <NUM>, an ice coating or an ice cover is added to the tray, which is then loaded with a bulk product, such as a slab of meat, at step <NUM>. In step <NUM>, the product is then processed, e.g., cut and removed from the tray, whose ice coating is now contaminated by the product. If enough ice remains atop the tray to be reused as determined by visioning the tray at step <NUM>, the top layer of the ice coating is removed at step <NUM> and a further layer of ice is optionally added (step <NUM>) before the tray is returned to receive bulk product. If it is determined that the ice coating is too contaminated or too thin to be reused, the tray is defrosted and the ice totally removed at step <NUM>. The defrosted tray is sanitized at step <NUM> before returning to the freezer to have an ice coating added at step <NUM>. As an option, the contaminated ice removed from the tray by the defroster or the ice refinisher can be reconditioned and reused as in steps <NUM> and <NUM>.

Claim 1:
A tray conveyor (<NUM>) comprising:
a track (<NUM>) having an array of electromagnetic drive coils (<NUM>) extending along the length of the track (<NUM>) and defining a conveying path;
a coil driver (<NUM>) driving the drive coils (<NUM>) to produce an electromagnetic flux wave that travels along the length of the track (<NUM>);
a tray (<NUM>; <NUM>') conveying products (<NUM>) through a process, the tray (<NUM>) including:
a top (<NUM>);
a bottom (<NUM>);
a permanent magnet array (<NUM>) between the top (<NUM>) and the bottom (<NUM>) producing a magnetic field that interacts with the traveling electromagnetic flux wave to produce a force that propels the tray (<NUM>; <NUM>') along the track (<NUM>); characterized in that the tray conveyor further comprises,
an ice coating (<NUM>) covering at least the top (<NUM>) of the tray (<NUM>; <NUM>'), wherein products (<NUM>) sit atop the ice coating (<NUM>) on the top (<NUM>) when the products (<NUM>) are undergoing the process;
and a freezer (<NUM>) producing an ice cover and a cover applicator on the conveying path depositing the ice cover on the top (<NUM>) of the tray (<NUM>; <NUM>') to form the ice coating (<NUM>).